I'm not really sure if you're going to school to learn how to paint or if you're learning as a hobby or what, but, and I'm sure you know this, the body work and prep of the car is just as, if not more important than the actual spraying of the paint itself. Go over the body over and over until you think it's perfect. Have other people (that know what to look for) check it out and see if they can find any imperfections. When the moment of truth comes, make sure the car is COMPLETELY clean. No dust, no dirt, no sanding residue, nothing. All this can be disturbed by the air pressure when you pass the spray gun over it and cause dust to get in your paint. Then you'll have to buff it out and what do you get, SWIRL MARKS!!!!
Common areas of premature paint chipping are edges of panels (doors, hood, trunk lid, wheel well lips). Make sure you sand these areas carefully, and preferably down to the metal.
Do the job right and paint the underside of the hood, tunk lid, and the door jambs. Sand all these parts as you would the rest of the body. It really completes a nice paint job.
Remove as many trim pieces as possible. Emblems, door handles, drip rails, chome moldings, bumpers, etc. aren't that hard to remove, and it makes the paint job look much better if you prep these areas nicely with the parts removed, then reinstall them after the paint has dried. Don't try to mask these parts off, it won't work and it will look bad. Plus it's a lot of fun to install these parts after it's painted. Really brings the car together nicely. Remove any scoops and the fender/quarter panel extensions and paint them separate. Buy new rubber gaskets for these pieces if applicable.
Also, make sure you do a great job of masking off. Do the undercarriage, wheels/wells, interior, glass, engine, exhaust, etc. Don't leave anything exposed and just say "I'll just clean it off after it's painted." It's a huge pain in the butt and the paint's hard to get completely off of some things. It makes the job look much more professional when you're done if there's not overspray on anything.
Another tip is this: AFTER the car is painted, coat the wheel wells/floor pans with some black rubberized undercoating. It sets the paint off nice and makes the car look much cleaner.
I hope these things help you out. If I think of any more, I'll post them. Good luck with the paint job!