95 SEO Tips and Tricks for Powerful Search Engine Optimization

Write great content (HIGH PRIORITY)
Great content is where it all starts. You can have all the keywords in the world, but if your content is no good, people won't stick around on your site and search engines won't find your site valuable.

Write unique content (HIGH PRIORITY)
Unique content is important too. You need to provide content that has different information than what is on other sites and other Web pages.

Add new content all the time (HIGH PRIORITY)
Sites that have new content added on a regular basis are seen as more reliable than sites that rarely do. This also helps you to increase the amount of relevant content on your site, which also improves your rankings.

Create a great keyword phrase (HIGH PRIORITY)
The first thing you should do when working on search engine optimization is find a great keyword phrase for that page. You shouldn't try to optimize your entire site to one keyword phrase - instead focus on writing pages for specific keywords and phrases.

Choose a phrase that is popular, but not too popular (HIGH PRIORITY)
When trying to decide on a keyword phrase, you want to find one that is popular but not extremely popular. This may seem counter-intuitive, but the reality is that extremely popular keywords are very desirable and so very competitive. It's better to try to optimize for keywords that you can rank higher. You'll get more page views from a less popular keyword when you're on the first or second page of the search engines, than from a super popular keyword that you only make it to page 50 of search engines.

Write an accessible site (HIGH PRIORITY)
Accessible HTML is accessible to both search engine spiders and screen readers. The more accessible you make your pages, the easier it will be for search engines to read and rank your pages.

Use the keyword phrase in your title tag (HIGH PRIORITY)
The title tag is one of the most important tags on your Web page. And placing your keyword phrase in the title tag, preferably at the beginning, is very important to get that phrase into the search engines. Plus, that puts your keyword phrase as the link in the search engine index.

Get a domain with your keyword phrase (HIGH PRIORITY)
Putting your keyword phrase in your domain name is a great way to optimize for that phrase.

Use the keyword phrase in your URL (HIGH PRIORITY)
Even if you can't get your keywords into your domain name, you can put them into your URLs. Search engines read the URLs and assign value to the text they find there.

Use your keyword phrase a lot, but not too much (HIGH PRIORITY)
The ratio of your keywords to the rest of the text on your page is called the keyword density. It's important to repeat your keywords in your document, but not too much. Keyword density should be between 3 and 7% for your primary keyword phrase and 1-2% for any secondary keywords or keyword phrases.

Use your keyword phrase in headlines (HIGH PRIORITY)
Headline tags (h1, h2, h3, etc.) are a great place to use your keyword phrase and secondary keywords. Search engines recognize that headlines are more important than the surrounding text, and so assign greater value to keywords found there.

Use your keyword phrase in anchor text of links (HIGH PRIORITY)
Link text is another great place to put your keyword phrase. Links stand out on most Web pages, and so are given higher priority than surrounding text.

Ask other people for links to your page (HIGH PRIORITY)
A great way to get inbound links is to simply ask for them. But remember that excessive cross-linking can be viewed as spammy, so be careful about trading links or otherwise buying links on external sites.

Try to get your keyword phrase inside incoming links (HIGH PRIORITY)
Inbound links are a great way to improve your page rank. But you can't really control how people link to your pages. Chances are they won't use a phrase that has anything even remotely close to your keyword phrase. Remember that they are doing you a favor by linking to you. If it makes sense, you can ask them to change the text of the link, but be careful, as people can be very touchy, and you might just get your link removed.
Another way to get your keyword phrase in inbound links is to provide your customers with the link text ready-made. For example:
Please link to this page: <a href="http://seo-mama.com">SEO Tips and Tricks</a>

Try to get links from reputable sites (HIGH PRIORITY)
Reputable sites that link to you will increase your reputation. After all, if a reputable site feels that your site is valuable enough to link to, that means that your page has more value. You can tell if a site is considered reputable both by how high it appears in search engines and it's Google PageRank. Also, .edu sites have a higher reputation because they represent schools and universities.

Try to get links from similar sites (HIGH PRIORITY)
Inbound links from sites similar to your own are important as well. This indicates that your site does have content related to that topic. Plus, it indicates that your competition finds your site valuable, and that gives your site more credibility.

Try to get links from .edu, and .gov sites (HIGH PRIORITY)
Sites that are on .edu and .gov top-level domains have a large amount of credibility because they are very difficult to get. So if you can get the designers of those sites to link to you, that gives your site more credibility as well.

Create as much content as you can (MEDIUM PRIORITY)
Content is king. The more content you have on your site, the more there is to be indexed and appear in search engines.

Keep your site content inside one theme (MEDIUM PRIORITY)
The theme or topic of your entire site is important as well. If you have a lot of pages all around one basic theme, that will lend more credibility to each page that follows that same theme.

Keep your site live as long as possible (MEDIUM PRIORITY)
Older pages (at the same domain) will rank higher than newer ones.

Create a sitemap (MEDIUM PRIORITY)
Search engines love sitemaps - not necessarily for ranking, but for finding links on your site. It's not critical that you create an XML sitemap or Google sitemap, plain HTML sitemaps work just as well.

Create an XML sitemap or Google sitemap (MEDIUM PRIORITY)
Search engines love sitemaps - not necessarily for ranking, but for finding links on your site. It's not critical that you create an XML sitemap or Google sitemap, plain HTML sitemaps work just as well.

Use 301 redirects for permanent redirects (MEDIUM PRIORITY)
When you redirect your pages, you should always use a 301 http server redirect. This tells the search engines that the redirect is permanent and that they should change their index to use the new URL. Spammers use other types of redirects (HTTP 302 redirects and meta refresh), so they are not a good idea to use.

Use 302 redirects only for long or ugly URLs (MEDIUM PRIORITY)
HTTP 302 redirects are for temporary redirects. The only time you should use them is for redirecting ugly URLs to more user-friendly ones. This tells the search engine that the ugly URL should not be removed from the index, because the user-friendly URL is just to make the URL palatable. Keep in mind that many spammers use 302 redirects to fool search engines. So be judicious in your use of them.

Get as many inbound links as you can (MEDIUM PRIORITY)
Links are important, especially from sites other than your own. These are called inbound links. And if you get a lot of inbound links, that will help your page ranking. Remember that 1-2 links from high-reputation sites are better than 10 links from link farms.

Put your keyword phrase in the first paragraph (MEDIUM PRIORITY)
Repetition of your keyword phrase is important in your content. But it's especially important in the first one or two paragraphs of text. And if you can repeat it once in the first paragraph that will help up it's priority.

Put your keyword phrase at the top of the HTML (MEDIUM PRIORITY)
More than just the first paragraph, you should try to move your content towards the top of the HTML document. And that includes your keyword phrase.

Put your keyword phrase in alternative text (MEDIUM PRIORITY)
Images are a great place to put your keyword phrase - in the alternate text. This is a way to add your keyword phrase into your document without being repetitive to your readers. But be careful not to overdo it - as you don't want to appear to be keyword stuffing. That could get your site banned.

Increase the font size of your keyword phrase (MEDIUM PRIORITY)
Search engines understand that fonts that are larger than the standard font size on the page indicate text that is more important. Use CSS or the font tag. Apply font size changes to headline tags as well.

Format your keyword phrases to stand out (MEDIUM PRIORITY)
Use <strong> and <em> where appropriate to make your keyword phrases stand out. Search engines can read those tags, and will recognize that text that is emphasized is often more important than the surrounding text.

Write a descriptive meta description (MEDIUM PRIORITY)
Search engines use the description meta tag as the description in their index. So it's important to describe your pages accurately. This helps customers find your pages, and search engines to index them.

Link to your page from within your site (MEDIUM PRIORITY)
Links are important, and linking from one page to another on your own site is a very easy way to get links. They aren't as important in search engine ranking as links from external sites, but they do help. If nothing else, they help the search engine spider find all the pages on your site.

Put up links that flow within the text (MEDIUM PRIORITY)
Links that make sense within the context of the document (whether from external or your own site) will rank higher than lists of links or other forms of artificial links. This is because search engines value content and links that make sense within the context of the content are more definitely related to that content than links that are inside lists.

Keep asking for inbound links (MEDIUM PRIORITY)
The older the links are the better. If you get 100 links added all at once, it appears to the search engines that you are buying link placement, and that can be construed as spamming.

Get linked in DMOZ and Yahoo! (MEDIUM PRIORITY)
DMOZ and Yahoo! and other directories show that your page is related to the contentin that section of the directory.

Periodically check your outbound links for page rank (MEDIUM PRIORITY)
Whenever you add an external link on your site, you run the risk that it changes from the site you linked to into a link farm or "bad neighborhood". By periodically checking the PageRank of the external sites you link to, you can remove links that have gotten bad. This will help you make sure that your page's credibility is not reduced by who you are linking to.

Link all major images (MEDIUM PRIORITY)
It's important to always link images because people click on images. And search engines value content that has been linked. The key is to always include alternative text, so that the search engine has text to rank. Any image that your customer can see on the page should be linked.

Keep your pages up-to-date (MEDIUM PRIORITY)
Pages that are regularly updated are given priority over pages that are older and ignored. But you should do more than simply fix typos or make small changes, regular, extensive updates are more effective than minor updates.

If you must use frames, always use the noframes tag (MEDIUM PRIORITY)
Frames and search engines don't mix well. But if you must use frames, then you should always include an extensive noframes version of your site. And by extensive, the best way to get your site indexed in search engines is to completely rewrite it in your noframes version.

If you must use Flash, always include alternative text (MEDIUM PRIORITY)
Flash and search engines don't mix well, but if you must use flash you should include alternate text that describes exactly what the Flash element includes. And if you use Flash for your entire site, you should always do an alternate version of the complete site in HTML so that search engines and non-Flash browsers can view it as well.

Use Flash for non-critical pieces of a page (MEDIUM PRIORITY)
The best use of Flash on websites is as small portions of the site, preferably non-critical portions. Search engines can't view Flash, they see them as images. According to Google Webmaster Central, sites that effectively use Flash "use Flash for rich media but rely on HTML for content and navigation."

Keep your pages close to the root directory (LOW PRIORITY)
The higher your pages are in your sub-directories, the better they will rank in search engines. This is because pages that are listed right off the root directory are typically more important than pages that are found four or five levels deep in the site.

Use the meta keywords tag and include your keyword phrase (LOW PRIORITY)
Meta tags are a very popular way to improve search engine results, but the fact of the matter is that some major search engines don't use them at all, and others only use them a little. It won't hurt to include your keyword phrase and any secondary keywords in the meta keywords tag, but don't expect it to work wonders.

Keep your kewords together (LOW PRIORITY)
Search engines rank keywords in pages regardless of where they are found. But if you're trying to rank well for a specific keyword phrase, keeping the keywords together will insure that the search engines recognize that they are related.

Use your keyword phrase in your meta description (LOW PRIORITY)
Most search engines use the meta description field as the description in their search results. So it's important to have a good description. Including your keyword phrase in the meta description tag is one more place that the search engines can see your keywords. This isn't a magic bullet, but it is a good idea.

Set your language meta keyword (LOW PRIORITY)
If your page is in a language other than English, you should set the language meta tag so that search engines (and other user agents) know what language it's in. Most search engines have other ways of telling what language the page is written in, but they do use that tag, and it could help you rank higher in searches in that language.

Optimize for a few secondary keywords (LOW PRIORITY)
Once you have a keyword phrase, you can choose one or two other keywords to optimize for as well. But be careful with these - make sure that the density of your secondary keywords is no more than 1-2%. Any higher and you risk confusing the search engine and diluting the power of your primary keyword phrase.

Use your keyword phrase in named anchors (LOW PRIORITY)
A named anchor (also called a bookmark) is a useful tool for creating navigation within a Web page. But for search engines, it also indicates that the text defined by and following the anchor has more significance. If you use your keyword phrase in some of your named anchors, that will give that text more prominence.

Use different forms of words for your keyword phrase (LOW PRIORITY)
This is also called stemming. Most search engines recognize that one word stemmed from another is really the same word. For example, plural versions of nouns (dog and dogs), gerunds and active verbs (dig and digging), and so on. By using different forms of your keywords, you can make your page more interesting for your readers, while still optimizing for search engines.

Use synonyms for your keywords (LOW PRIORITY)
Synonyms, like keyword stemming is another way to mix up your text for your readers while still optimizing for search. Most modern search engines have a powerful synonym library and so recognize that words like "dog" and "canine" mean the same thing. Be careful using this technique on non-English pages, however. Most search engines were developed in English-speaking countries, and have more extensive English vocabularies than other languages. Also, you should remember that tools like keyword density readers often don't recognize synonyms, so your page may be denser in keywords than they report if you use a lot of synonyms.

Don't link a lot to external sites (LOW PRIORITY)
Linking to sites not on your site is a good idea, but don't fill up your pages with them. At best, you will dilute the effectiveness of your page in the search engines, and at worst your page will look like a list of links and get slightly penalized by search engines. Also, when you have lots of external links, you have more to check on a regular basis, to make sure that those pages don't go bad or turn into "bad neighborhoods".

Register a separate domain instead of a sub-domain (LOW PRIORITY)
Subdomains are a nice way to create new websites without needing to register a new domain. This site is a subdomain of About.com - webdesign.about.com. But subdomains are not as recognized by search engines (or customers for that matter) as separate sites. For example, most people who link to my site link to it with a title of "About.com." But if you were to go to www.about.com, you'd get a very different impression of my site than the true URL of webdesign.about.com. The other problem with subdomains is that most people think that URLs should start with "www". Sometimes www.subdomain.domain.com will work, but sometimes it won't.
If you can, you should move all sites that are on a subdomain onto a real domain name of their own.

Register a .com domain over a .biz or .us domain (LOW PRIORITY)
Trying to find a good domain name can be challenging, especially on the .com top-level domain (TLD). But finding a good .com domain will rank higher than a similar domain on the .biz or .us TLDs. And if you can get a .edu domain (because you're a school or university) your site will have more credibility instantly. Some SEO services feel that a .org TLD is better than a .com, but they aren't any more difficult (in general) to get than a .com domain, and while search engines might give them some priority now, they will probably lessen that as .org domains become more common.

Use hyphens to separate words in domains (LOW PRIORITY)
When you're putting keywords in your domain and URLs, you should consider separating them with hyphens (-) rather than mashing them all together or using underscores (_). Search engine spiders can't tell where a word ends and begins without cues like hyphens, and most computers recognize hyphens as the end of a word, but see underscores as part of the word.

Use hyphens or underscores to separate words in URLs (LOW PRIORITY)
Just like your domains, you should separate words in your URLs with hyphens (-) or underscores (_). Hyphens are better, but outside of the domain, underscores can work. Hyphens work better because many search engine spiders recognize hyphens as the end of a word, but see underscores as part of the word. Also, underscores can be seen as a space by your customers (because the underline of the link and the underscore merge together), and they will then get frustrated if they try to type the URL with a space and can't get to the page.

Write short pages (LOW PRIORITY)
The shorter your page is, the fewer times you need to repeat your keyword phrase and keep the density just right. Plus, short pages load more quickly, and so your readers will appreciate it. Keep pages under 30KB in size. Split long pages into multiple pages and optimize each page.

Use JavaScript with care (LOW PRIORITY)
As long as your scripts are valid and don't break your HTML, most search engines will ignore them. But don't rely on JavaScript to improve your rankings - most search engines ignore content inside JavaScript.

Include text transcripts of podcasts and sound files (LOW PRIORITY)
Like images and Flash, search engines can't index the content of sound files including podcasts. By including a transcript of your sound files and podcasts, you give search engines more text to index.

Don't host your site with a host that allows spammers (AVOID)
This means any type of spammers, but especially search engine spammers. If you don't know what your host's policy is towards spammers, find out. There should be something in their terms and conditions about malicious activity. If your IP is blacklisted, you'll be blacklisted right along with it, even if your site is completely innocent.

Don't host your site with a host that is down a lot (AVOID)
While search engines won't deliberately discriminate against a site that is down, if they can't get to your URL because it's down, they can't index it. And if your site is down several times when the spider tries to access it, it could be flagged as gone, and then the spider won't come at all. Find out from your hosting provider what their uptime rates are and what they guarantee. Less than 97-98% uptime is bad.

Don't omit alt text for images especially images inside the text (AVOID)
Images inline with your text can dress up your Web page, but if you leave off the alternative text (alt text) search engines won't pick up the content relevance. Also keep in mind that the heavier your page is with images, the less likely that search engines will rank it highly. Text is what gets ranked in most search engines, and alt text is a poor alternative.

Don't use images instead of text links (AVOID)
Search engine optimization is all about text, and if you use images instead of text, even if you have good alt text, search engines will have a harder time ranking your site. This is especially true for navigation. Search engine spiders crawl through your site by following links, and links on images can be more difficult for them to follow or rank than text links. Using images instead of text makes your pages slower for your customers too. You're better off styling your text with CSS, than using images.

Don't misspell your keywords in your content (AVOID)
It can be very tempting to try to optimize your site for misspellings. And while it won't hurt your site in the search engine rankings - especially if you decide to use the misspelled version as your keyword phrase to optimize on. It will hurt your credibility with your customers. For every one person who misspells the word, there are at least two to three who know the correct spelling. And if they end up on your page for some reason, they will just think you are unprofessional. Plus, many browsers and search engines have spell checkers built into the forms, so the popularity of misspellings will continue to lessen as time goes on.

Don't try to optimize for more than 2-3 keywords and phrases (AVOID)
This is called keyword dillution. If you have too many topics on a given page, it will be hard for both search engines and your customers to determine what you're talking about. If you have a lot to say on several topics, it's better to write multiple short pages on each topic, than to try to cram them all into one long page.

Don't use your keyword phrase too much (AVOID)
Keyword stuffing is the practice of repeating your keywords or keyword phrases over and over in a page until there is nearly no other text than the keyword phrase. Check your keyword density to determine if you have used it too much. 10% or higher is too much.
If you are too blatant about stuffing keywords, you could get your site banned from search engines.

Don't rely on links from domains on the same IP (AVOID)
While Google doesn't discriminate against domains that have the same IP (for example, domains that use virtual hosts), other search engines may. So it's best to avoid trying to increase your inbound links with links from other domains that you own. The same is true for domains hosted on the same hosting provider (coming from the same C-level IP address). Google doesn't penalize sites like this, but other engines might.
This is another situation where if it becomes apparent that you're doing it, you could get all your sites banned from search engines.

Don't have more than 10 words in your URL (AVOID)
While you want to have keywords in your URL (and domain if possible), longer URLs tend to look more spammy to both customers and search engines. However, this isn't a serious issue, and if you need to have 11 or 15 words in your URL, it shouldn't be a problem, as long as you aren't doing it all the time.

Don't use URL parameters if you can avoid it (AVOID)
Parameters on URLs make them long and hard for anyone to read. And search engines can get confused by them, especially if the parameters are meant to hold customer information, and not indicate a separate Web page. Also, as I mentioned elsewhere, search engines don't always rank dynamic pages as high as static pages, and most dynamic pages use parameters on the URL to indicate the correct page. If you must use parameters, you might want to consider doing a URL rewrite to static URLs, at least for your most important pages.

Don't use dynamic URLs (AVOID)
In general, spiders tend to prefer static URLs to dynamic ones. It is possible to rank high with a dynamic URL, but it's easier if you redirect dynamic URLs to shorter, static URLs.

Don't use session IDs (AVOID)
Like dynamic URLs, search engines don't tend to like URLs with session IDs on them. In fact, session IDs seem to cause even more problems with search engine spiders than plain dynamic URLs. The problem is that every time the spider comes to a site with session IDs it can index that site as a completely new URL - even though the content is identical. This can lead to the search engine thinking you are trying to spam them with identical content, and could even get your site banned if it got bad enough. Google guidelines now state that id= URL parameters are okay, but that doesn't mean that other search engines won't choke on them.

Don't rely on AdSense to boost your rankings (AVOID)
AdSense is a way to earn money on your website. But contrary to popular believe, having AdSense ads won't improve your ranking in search engines, even Google. They won't hurt your rankings either. It's perfectly fine to use them, but don't expect them to improve your search rankings.

Don't rely on AdWords to boost your rankings (AVOID)
AdWords is a way to advertise your sites on Google. While you can pay to get high rankings in advertising venues, having an AdWords account won't help your rankings in natural (non-paid) search, even in Google. It won't hurt your rankings either. You can use AdWords to get more clicks to your website, but they will appear only in paid search locations, not in the natural search.

Try to get your site off link farms (AVOID)
You should never link to a link farm. And while search engines state that they don't discriminate against sites that are linked to from link farms, it's a good idea to try to keep your site off of them, if only to avoid contamination by association.

Don't link to link farms (AVOID)
Google refers to spamming sites as "bad neighborhoods" and if you link to them, you will end up with a lower PageRank. If you suspect that a site you want to link to is a "bad neighborhood", check their PageRank and see if they commit any obvious SEO no nos. If they do, or you think they might, then you shouldn't link to them.

Don't create pages of links (AVOID)
Pages of links are boring both for your customers and for search engines. Most search engines value links that are in context and appear related to the page as a whole. Note, however, that many social networking sites (like Digg and del.icio.us) tend to favor pages that are lists of links, so sometimes it can be advantageous to write them anyway, just don't expect them to rank high in search engines.

Don't link to and from the same site repeatedly (AVOID)
This is also called link spamming. At best, search engines will look at the links you have on your page, and only count the first one or two towards optimization. And at worst, your site might appear to be a spammer, even if you're not linking to a "bad neighborhood" or are in a cross-linking scheme. You want to avoid looking like you are paying for links.

Don't get into link circles (cross-linking) (AVOID)
When several sites have links set up in a circular (or more complex) pattern (site A links to site B links to site C links to site A), it can look like you're paying for links. Don't assume that because your average customer won't notice the pattern, the search engine won't either. Since search engines give some priority for links, they want to reward "honest" links, or links that are not paid for. If it looks like you might have paid for the links (even if you haven't) your ranking could be penalized slightly.

Don't have broken links on your site (AVOID)
Broken links make your site look bad, and they imply that you don't manage your site very much. Search engines want to have only the highest quality results, so they may penalize sites with lots of broken links. Use a link checker periodically to make sure that your links are still valid.

Don't use the meta refresh tag to redirect users (AVOID)
It can be very tempting to set up redirects on your site with the meta refresh tag, but this can be a bad idea. Many spammers use them to try and fool search engines into thinking that a page is about one thing, and then refreshing to something completely different. Meta refresh also doesn't give information to the search engine about why the redirect is occurring. It's much better to set up a permanent HTTP 301 redirect when you need to redirect your customers to a new URL.

Don't use 302 redirects (AVOID)
A HTTP 302 server redirect is supposed to be used when a page is only temporarily moved from one location to another on a server. Spammers use 302 redirects because that gives them many more URLs to the same final page and thus many more ways to get to that page.
The only time you should use a 302 redirect is if you have ugly URLs with lots of parameters on them. The 302 redirect tells the search engine that this is not a permanent redirect, but rather an alternate URL. For all other redirects you should use a 301 redirect instead.

Don't make constant minor changes to content (AVOID)
While you want search engines to see that you update your content, making minor changes (like correcting spelling errors, or changing 10 or 20 characters) implies that you're just trying to get the updated date changed. This looks like you're trying to fool the search engines into thinking that you update your pages more than you actually do.
Do spend time updating your pages, but make the updates substantive.

Don't separate content artificially (AVOID)
Don't display different content based on IP, browser type or version, operating system or whatever. This is very tempting for most Web designers, as it's a way to show you know how to write JavaScript or another programming language. But it can look like you're trying to trick the search engine - showing it something other than you show your readers.

If you really must display alternate content based on some artificial measure, create separate Web pages for each, rather than using the same URL for all the content. Or, keep the content that is different as minimal as possible, don't build an entire new site for each IP or browser type.

Don't violate copyright or other laws (AVOID)
Most search engines have terms of service that ban sites that break the law. Copyright infringement is the easiest way to break the law on the Web. Don't assume that because something was posted to the Web it is legal for you to reprint it, get permission or link to the article instead of copying it. Search engines will ban your site if you regularly steal content or break other laws.

Don't duplicate content on your site (AVOID)
One trick that spammers like to use is to create one page and then post it in numerous locations, both on one domain and on others. The idea is that if there are enough copies of the page, it will get seen by more people. But search engines don't like duplicate content as it's a waste of space on their servers and does not provide good information to their customers. If a search engine suspects your site is spamming them with multiple copies, your site could be banned.

Don't use robots.txt to ban large portions of your site (AVOID)
In general, using a robots.txt file to keep certain areas of your site off-limits to spiders can be a good idea. But if you ban significant portions of your site (more than half), search engine spiders may mark your site as "forbidden" in general and simply stop spidering your site as often. And if your site is spidered less often, fewer pages will be added to the directory and updated in rank.

Don't write bad or incorrect HTML (AVOID)
Most search engines don't deliberately discriminate against badly coded pages, but if the spider can't read the page because the HTML is bad, then it won't get indexed. Make sure that you validate your HTML regularly and that any issues there are don't affect the page being viewed by a simple user-agent or screen reader.

Don't use frames (AVOID)
Frames and search engines are not a good combination. While search engines are getting much better at reading framed websites, they still don't tend to rank as well as non-framed sites. And even if you get decent ranking, you might not get the clicks because the search engine doesn't know what to display as a title or description of your page.

Don't create Flash splash pages (AVOID)
Search engines can't read images, and they see Flash as a giant image. Flash and search engines don't mix well. If you don't have extensive alternative HTML that displays when Flash is not enabled, then your site won't rank well in search engines. Be sure to test your site with a browser with Flash disabled to find out what the search engine sees. You might be unpleasantly surprised.

Don't write Flash-only sites (AVOID)
If you're going to use Flash on your site, you must have an HTML version that displays when Flash is enabled. It can be tempting to put in just a single line or two of HTML as your non-Flash alternative, after all, you've done so much work on the Flash site. But since the search engines only see the HTML, that's what they'll rank, and you won't rank high with just a tiny version of your site in HTML.
If you must use Flash as your site, and you want to rank well in search engines, you need to be prepared to write your site twice - once in Flash and once in HTML.

Never redirect to another domain (AVOID OR GET BANNED)
Redirecting to another domain is not a 100% guarantee that you'll be banned from search engines. But it is a very common spammer trick used in conjunction with doorway pages and cloaking. If you set up a redirect that goes to a new domain, you need to write it as a 301 HTTP redirect, not a 302 or meta refresh. This tells the search engine that this redirect is permanent, and they should change to the new domain in their directory.
Be Careful Redirecting to New Domains - You Could Be Banned
Since this trick is commonly used by spammers, it's a very good idea to avoid doing it. Search engines can be very hard to get back into if your site is banned by mistake.

Never link invisible images (AVOID OR GET BANNED)
Invisible images are images that are 1x1 pixels in size and cannot be seen by the naked eye on a Web page. Since links are given some priority in ranking a Web page, linking images that cannot be seen by your customers appears to be aimed only at search engine spiders.
Don't Link Single Pixel Images - Your Site Will Be Banned
This is similar to hiding text or displaying different content to search engines than to your customers. And don't assume that search engines can't read CSS or HTML tags that resize full-sized images. If you do this to optimize your pages, your site will be banned.

Never include invisible text on your pages (AVOID OR GET BANNED)
Hiding text by making it the same color as the background color may fool your customers, but it won't fool search engines. Another variation of this is where you make the font size so small that it's unreadable by the naked eye.
Don't Hide Text - Your Site Will Be Banned
Search engines understand CSS and font and background colors. They also recognize that a font-size of 1px is not going to be readable. Text that is hidden from your readers but visible to search engines is considered spam and will get your site banned.

Never create doorway pages (AVOID OR GET BANNED)
Doorway pages are very simple HTML pages that are written to optimize heavily on one or two keywords or keyword phrases. And they are programmed so that search engines spiders see them, but regular readers are taken to the real site.
Don't Use Doorway Pages - Your Site Will Be Banned
Doorway pages are designed to trick search engines into thinking that the site has a specific keyword relevance that it may or may not have and they are pages meant to be seen only by the search engine. So, most search engines will ban sites from their directory when they discover you use them.

Never display different content to a spider than customers (AVOID OR GET BANNED)
This is often called cloaking because it is an effort to cloak what your site delivers in something that might be seen as more palatable to search engines. It can be very tempting to use cloaking, but while it might give you better results at first, search engines don't like it.
Don't Cloak Websites - Your Site Will Be Banned
Search engines want to provide a resource of information that is real, not something that has been doctored to give artificial results. When they discover that your site is cloaking, it will be removed from the search directory.