Not to be rude, but I think the best way to sell your iOS app is to make a really good one.
If your great game gets lost down the charts before it's seen, then your success relies on people finding it using App Store search and your keywords. From my experience nobody does this, except for Utilities.
Having a really good app helps it stay on the top, but not necessarily get to the top at all. We've seen pretty poor games get to the top (and usually falling down quickly) and great apps never making the top (due to ie. poor shots or description).
It's not that simple.
So, while it may not be a charts buster, I enjoy my game, and it's one of three that I play (the other two: Arkanoid-style game, and a free card game).