lucy24 - 8:58 pm on Apr 17, 2013 (gmt 0)
Might help to work in the other direction. Look at your logs. See what search terms were used by the people who actually do land on your site. (Assuming for the sake of discussion that you're able to see at least some of the q= terms.) Build outward from there.
If some searches are obviously wrong-- you don't have what the searcher is looking for-- tweak your site so those terms don't trigger search-engine hits followed by immediate retreats. You don't want them, and they make you look bad to search engines.
If some nice terms come through in the 4-to-10 range, work on making yourself more attractive so you can claw your way a little higher. But check first: If you're no. 4 and nos. 1 through 3 are amazon, wikipedia and youtube, you're not going to go any higher.