Colors - relevant & unique content - custom images.
The keywords above should be matched to who your target group is. In other words; who's most likely going to search for/type in the domain and what does your user group expect to see?
With the appropriate colors, matching the general objective of your site: relaxed, aggressive, etc. and the right visuals, you're giving an incentive to stick around and consider using the links on the site.
Once you're done delivering what your target group is looking for, make sure the keyword(s) are set correctly, so that your users find relevant content to their searches.
That's the beginning in my book of domain optimization - from this point on it's subtracting or adding content and images, changing keywords, etc. - basically a trial and error scenario. If done right and adhering to many tips that Netmeg, Varon and a few others can deliver, you have a viable chance to succeed.
Best of luck!
M.
