Search Engine Optimization (SEO) is a key feature to a website's success. There are numerous search engines available; Google, Yahoo, MSN, and AskJeeves are the top contenders. Search Engine algorithms (a.k.a. Search Engine Spiders) are forever evolving but there are basic standards to follow that will always be important when a search engine is indexing your site.

Relevancy

There have been numerous sites in the past that lacked design but had great Search Engine Optimization and are ranked very high for searches. The most important thing to keep in mind is relevancy. A page on your site should not veer off topic and you should repeat the keyword(s) several times within the page.
Example:
Say you have a page about family reunions. You would obviously want to entitle the page Family Reunions and within your first few paragraphs you should also use these words at least a couple of times because the first 250 words on a page get better relevancy.

Inbound Links

This does not mean your site should not be well designed. A well designed site will have many visitors and many repeat visitors, which leads me to the next factor of Search Engine Optimization, inbound links. These inbound links come from people that link back to a certain page within your site. To be more specific they link back to your page with keywords as the anchor tag. It is good practice to give your guest predetermined HTML code to use to link back to your site. By doing this you take control of what phrases your inbound links will contain and search engines will better rank you for those key words.
Example:
Continuing with the family reunions page, a well executed HTML code to use for inbound links would be:
<a href=\"http://www.yoururl.com/family-reunions.html\" title=\"family reunions\" alt=\"family reunions\" >family reunions</a>
This may seem like overkill but, if you think about it, you clearly get your message across to the Search Engine what your page is all about.

Images and Design

Keep in mind that a Search Engine Spider (the software that search engines use to index your site) is nothing more then a complex computer program. It has very little idea what your site visually looks like or what your images on the page look like. Which is why poorly designed sites with good optimization tend to index fairly well. One way to tell the search engine what your images are is by using alt tags. You can use this to your advantage by naming unimportant images the key word that you are trying to list for.
Example:
We'll continue with the family reunions page. On this page you may have a picture of uncle Bob. You could list the picture as:
<img src="images/bob.jpg" alt="uncle bob" />
But this would not help your page list for the term Family Reunions. The proper way to go about it would be listing the picture as:
<img src="images/bob.jpg" alt="Family Reunion: Uncle Bob" />
This way you get the best of both worlds: the family reunion keywords and the uncle bob description.

This is a very basic, yet solid, explanation of Search Engine Optimization. If you use these methods alone you will do fairly well (Top 100). If you choose to use my expertise, we could sit down and discuss popular terms that would make your site extremely successful. Top 50 in most search engines is not unlikely and Top 25 is a great possibility. I have worked with numerous sites that have large budgets on making their site #1 which could definitely be an option for you but it does come at a price.