This page explains in 21 steps how you can optimize your web pages for search engines like Google.
First things first: there is no way to cheat a search engine into liking your page better than others. In the end search engine optimization is all about providing quality content (Google loves content!), creating a valid page structure and meaningful navigation, as well as promoting your site to people who might be interested.

Keep in mind nothing described here is just optimization for the search engine; it will all help the end user visiting your site, the one that tries to find relevant information to a given subject, the one that wants to read through your content and navigate the site.

Need help for your site? Contact me for search engine optimization services.

Optimizing for Search Engines

1. Create Quality Content

This I'm afraid is the number one reason your site is going to be popular, with search engines as well as with visitors: quality content. Creating quality content is of course also one of the hardest things to do, or at least it takes serious time.
Also, never make the navigation of the page more important than the actual content itself (so don't use quite too many links or HTML "garbage").

2. Create a Lot of Content

The more pages you can provide, the better. Link them all together in a meaningful way. Don't create orphan pages.
For international pages, translate as many pages into as many languages as you can (or your budget allows).

3. Keep Content Fresh

Update your pages regularly; add pages regularly; in short, keep a site's content as fresh as possible. The search engine bot spidering your site will reward you by constantly visiting you.

4. Remove Duplicates

Keep your pages as unique as possible. Otherwise, the search engine might remove duplicates from its index.

5. Versatile, Precise Wording

In your texts, use different expression; change the wording even if you describe the same thing. For example if you are talking about "cheap noodles" also mention "inexpensive pasta". This increases the likelihood of targeting the right keywords. If in doubt, consult a dictionary with Thesaurus. And don't forget to spell-check your text.

6. Focus on Important Keywords

Make sure you know what target audience you're trying to reach with your page. Focus on how they might search for your site.

7. Create Valid HTML

Validate your HTML. Check your links. Follow the specifications published by the World Wide Web Consortium.

8. Create Structured HTML

Use headings (h1, h2), phrase mark-up (em, strong).

9. Provide text-alternatives

When you include an image that communicates something important, don't forget the alt-attribute. Think of how a blind user would read your site; the search engine bot is also blind to visuals.

10. Use Meaningful Meta-Data

Very important: Every page should have a unique title describing just what the page is about, using the important keywords.
Additionally, you might want to add a meta-description, as well as a few meta-keywords. The two however will not help much in your search engine ranking.

11. Keep It Simple

Don't rely on client-side scripting for anything important. Don't use forms or form elements to let the user navigate. No meta-refreshs. No frames, please. Avoid Flash. Use basic, simple HTML. (Like XHTML1 Strict or HTML4 Strict, along with CSS2.)
If you need special functionality, use server-side scripting.

12. Use Common Sense, Don't Rely on Tricks

Whenever in doubt, think about what a search engine must be good at in order to be popular; it must find pages relevant to what the user is looking for. Whatever you're doing, never try to be listed in a search result if your page is not actually relevant. You might be punished by the search engine. Avoid hidden content or "doorway pages" tailored to search engines.

13. Get a Reliable, Robust, Fast Server

Get your own top-level domain on a good server. Don't rely on free homepage services as they want to add things to your HTML and are in general not as reliable.

14. Keep Your Location

Don't move around your content every other week. Keep the file-names. Don't change folder names just for fun. In other words, whenever possible, ensure that old links to your site won't become outdated.

15. Create Meaningful File-names

Use non-abbreviated, meaningful file-names in accordance with the page's subject (e.g. "instant-noodles.html"). Do this not only for HTML files, but for images, folders, or other document formats (such as PDF, Word, Zip) as well.
Separate single words by a hyphen (but don't necessarily correct old file-names if they're online already). You might want to use a domain-name that is close to your topic, even if this might not show direct effect.

16. Publish Your Site in Directories

The Open Directory Project is the most important human-organized web directory today. Try to get into it and you will get a lot of links from many sites using the directory data.

17. Add Your URL to Search Engines

I would suggest mainly one place to add your (top-level) page, and that is Google's Add URL.

18. Communicate Your Site to Others

Publish your URL in relevant newsgroups, write personal emails to people you think might like it. Ask websites with similar subject to link to you. You can return the favor by linking to them.

19. Test Your Ranking and Fine-tune

Keep going to some search engines, mainly Google, and check how your pages fare upon entering what you would consider on-target keywords for your site. Also think about how others might phrase a search. See how competitive sites go on about it.

20. Keep Updated on Search Engine Technology

Regularly read up on what's happening in the world of search engines. Don't be satisfied with a good ranking now and know that an engines underlying search algorithms are likely to change in the future. Join a search engine discussion forum and read along. Consult the Google Webmaster Guidelines from time to time, if only to remind you you're doing things right.

21. In the End, Relax

There's not that much you can do after all. Do things right, don't cheat, create relevant content, have a meaningful structure and valid pages. Don't get nervous. Don't try to find easier ways. Don't re-submit URLs. Don't spam people. Just wait, build interesting content, and talk about it to the right people.