i'd love to be able to give you tips, i spray quite a bit for a living but sadly i'm crap at explaining things (tried teaching my lad to weld, disaster lol) but preparation is the main thing, don't think paint will hide imperfections (it won't),make sure you are in as dust free as possible environment, don't let anything with silicone in it (ie wd40) near your car, primer first, then wet flat it (1200 paper with water and fairy liquid) till its real smooth, apply first coat lightly (don't try and colour it with the first pass), wet flat lightly then start laying paint on,wet flat between coats if you want a good finish. patience is the best thing you can have and don't panic if you get a few imperfections, theres ways round everything, i should know lol. also depends what type of paint you are using, i use 2 pack all the time and its very forgiving and dries mega quick but is really bad for your health unless you're into air fed masks etc.