Focus on a few rich keywords.

It's a cliché, sure, but it's true: you cannot be everything to everyone. Rather than brainstorming a bunch of keywords and cramming them into your body text and meta tags, spend some time understanding your best-bet keywords and keyword phrases and focus in on one or two of them. This more targeted approach is not only easier to implement, but you are also more likely to improve your search engine ranking. When developing this focused set of keywords, use web metrics, and also consider your audience, your geography, and concentrate on descriptive language.