Please keep up the work... I think the BB world needs the app effort the iphone has received.
So ... how to make an app graphically pleasing and fun to use.... Don't reinvent the wheel - improve on it... Take some cues from the iphone apps - perhaps use the accelerometer &/or GPS in an innovative way.
I'd pay $5+ for a good simple(1-3 function) app. like this.
Graphics are important. Some buttons overlap and the screen appears crowded at times. Make your app interesting & fun to use...
Good luck. I'm sure your efforts will pay off...