That's one of my hobbies. You can learn a lot from these guys
https://www.autobody101.com/forums/viewforum.php?f=5
I've done a few day classes at at body shop supplies place. All I can suggest without going into too much detail is find a good paint supplier and use their products and stick with PPG or who ever. Don't mix and match brands and don't buy cheap paints.
A largish compressor with a VERY good desiccant filter, and Devilbiss or Iwata spray gun. And practice painting old steel filing cabinets. The recycling centers are fairly much giving the cabinets away so it's an easy flat surface to practice on.
Most of all it sounds fun what you are doing.