The best way to paint metal is a rather simple process: 1) sand or grind any imperfections or rust as best as possible 2) patch holes or use bondo filler if needed and smooth again 3) Apply a coat of primer (best results from an air powered spray gun; gravity fed is the best imo). let dry 4) apply desired paint colour with the spray gun (after its been cleaned with thinner). let dry 5) seal the paint colour with a clear coat finish. this is also applied with the spray gun after cleaning out the paint. clear coat comes in a variety of finishes from high gloss to flat matte.