Well if you go to your school and learn the basics, most of it is all trial and error, some painters have different ways of doing things with same results.
Like my flames are very long skinny and flowing, some make them bigger and tips not as long.
There is so much information out there you just need to go to a book store and look at all the books available on custom paint & choose the one that interests you the most and read it .

Or find a shop that needs a painters helper and see if he will hire you , but this will be hard if you dont have the basics of prepping a car for paint as, some painters dont have time to teach some one how to do it from the start .

SprayTech