Straight from the horses mouth

"Here are a few tips that can make sure your page can be found by a focused search on the Internet:

Think carefully about key terms that your users will search on, and use those terms to construct your page.

Documents are ranked higher if the matching search terms are in the title. Users are also more likely to click a link if the title matches what they're looking for. Choose terms for the title that match the concept of your document.

Use a "description" meta-tag and write your description carefully. After a title, users click on a link because the description draws them in. Placing high in search results does little good if the document title and description do not attract interest.

Use a "keyword" meta-tag to list key words for the document. Use a distinct list of keywords for each page on your site instead of using one broad set of keywords on every page. (Keywords do not have much effect on ranking, but they do have an effect.)

Keep relevant text and links in HTML. Placing them in graphics or image maps means search engines can't search for the text and the crawler can't follow links to your site's other pages. An HTML site map, with a link from your welcome page, can help make sure all your pages are crawled.
Use ALT text for graphics. It's good page design to accommodate text browsers or visually impaired visitors, and it helps improve the text content of your page for search purposes.

Correspond with webmasters and other content providers and build rich linkages between related pages. Note: "Link farms" create links between unrelated pages for no reason except to increase page link counts. Using link farms violates Inktomi content guidelines, and will not improve your page ranking." Source: http://support.inktomi.com/searchfaq.html