Should I mess with my keywords?

[juggernaut]

Ok well I just started getting listed like yesterday for about 2 key phrases. Im on yahoo and msn not google yet. My question is should I mess with the key phrases now in order to try an get listed higher for other phrases? I only have 1 html page to screw with and if I keep on optimizing this page its going to look like crap. I can only place so many of the key phrases in the body, title, etc before this whole page just looks like 1 large optized search engine page. The key phrases I'm getting listed under were not in my page but they are good ones so yesterday I added them.
Funny thing is they are not in my title or description. The stuff that is, has not shown under any SE. I would like to be able to stay on top of this now. But I'm a little scared that if I start fixing stuff that aint broken, well then Im going to break it and have to start all over again. Any ideas or advice please. Jugg..