In addition to what others have said:

For good rattlecan success, prep the frame well. Strip, sand, etc thoroughly. Prime, sand, prime, sand, then paint. Paint in multiple lighter coats, let them dry thoroughly. When the last coat is on, let everything cure for at least a few days. This reeeeeeally makes a pretty big difference.

Also, stick to good quality paint. Rustoleum is fine, though I haven't had the best luck with it. I've had better luck with DupliColor paints, specifically their engine enamels, which contain a ceramic element and are extremely durable once you let them cure. Stay the hell away from Krylon.

Sorry for the huge image, but here's a spraycan job: