I sanded old paint off with 180 grit sand paper, once all of it was off, i moved up to 320 grit sand paper. Then I washed it down used some wax and grease remover, tacked it and sprayed 3 coats of primer on it. wet sanded with 400 then 600 then 800. washed it again, used wax and grease remover, and tacked it, sprayed my base coat, tacking after each coat, then i clear coated it about 3 coats. and I sprayed with an IWATA LPH 400 spray gun, with a 1.4 needle size. and primer i also used an IWATA spray gun with 1.8 needle size.
Just remember, don't try to cover the pieces all in one spray, light and multiple sprays will make the paint look amazing, but for the clear you have to go alittle heavy but not TOO heavy, a medium wet coat is enough, then 2nd coat try to cover it all and try not to get any dry spray, overlap the sprays.