The key to a perfect paint job is the prep work. What method are you planning on using rattle can or HVLP gun? If you want a glass finish you have to sand off the orange peel and spray, sand, spray, etc... Good luck!
make sure you use a fine grit sandpaper and lightly wet it when you sand it. Its called wet sanding Im sure you could youtube or google some instructions or techniques.Use a block or some other flat surface so it sands evenly as well. Good luck.
Take your time, don't get anxious just because you want it done. It'll probably come out looking like crap and you'll have to do it again so do it right the first time. I'm speaking from personal experience.
I tryed using a sanding block but there are so many grooves and curves that i just found it easyier to just sand by hand. everyone says to use a very fine grit sandpaper but u can and should start with something pretty course, depending if you have rash, OEM paint, or what is already on it that you want to get off. I think i started with a 220 or 320 real lightly and then went to 600 1000 1500 2000 or higher if you can get it and then you dont need to worry about it after that couse it would just need to be sanded before and between clear coats, but if your buddy is doing that he should know better then me. (hopefully)
this is just what i did and it was alot of work but take ur time and have plenty of paper, especially the finer grits and use the courser grit very sparingly