I used to paint detail, custom paint, pinstripe, and full paint autos.
The more sanding (always wet), eventually getting up to the 1000s in grits, the better.
This will give you a smoother and even surface. Use florescent lights to check for straight reflections.
Near the end, many color coats (deeper and richer color), and many clear coats (protection and shine), ample sanding between each coat, then wipe and clean with alcohol (this will clean and slightly smooth out the coat), then next coat.
Finish with some buffing and polishing by hand.