It's not that hard, just a little time consuming.
Think of all the keywords that are relevant to your site, then go to
http://inventory.overture.com/d/sear...ry/suggestion/
and type each one in, make a list, delete all duplicates... and voila! you got a keyword listing for google.
Then all you need is a kick ass description.
One last tip, don't try to get top position, I find you can get better sales when listed in the 3 to 5 position.