Skillz I wouldn't use a single stage paint unless you want to paint it again in a year or two. That is really the only thing I disagree with his post. I have a degree in auto body repair and painting and work in a body shop so I like to think my knowledge is pretty right on. Use base coat clear coat for the best results everytime. Buy the dupont or PPG off brands (Nason or Omni), they work and spray about as good as dupont and PPG but are only a fraction of the cost. You should be able to get a quart of sprayable material for no more than $25-$30 depending on the color you pick. If you want it flat get a flat clear to spray over the basecoat. Also have the paint shop you buy the paint from print you out the spraying instructions, which they will do for free and will give you all the info you need to spray that exact type of paint. Remember to get strainers for the paint and make sure to mix it up well before spraying even if they shook it at the paint shop.
Before you spray anything remember to get your paint gun at the correct settings to spray a nice even spray pattern or the paint job won't turn out anyway. You want a even fan pattern about 6-8 inches tall and a inch or so wide that is even from top to bottom to avoid blotchiness.
Skillz is correct with spraying an etching primer on any bare metal before you spray on the primer. Just so nothing starts to rust through your paint job a while down the road. Then just follow the instructions you get with the paint. It will tell you how far to hold the gun away, the flash times to let the paint dry before coats. Make sure to use a tack cloth after letting the base coat dry before clearing to remove any small dust particles from sitting and drying before spraying the clear. This can save a paint job especially if you are not spraying in a booth and just in your garage.
Couple other tips, if you are spraying a paint with metal flake, it is a good idea to turn the air pressure up from 33 psi at the gun to around 40, hold the gun about a foot and a half to two feet away and do a quick pass or two like that. When I say quick I mean about twice as fast as you normally would. This more or less will mist a coat on and will help even out any blotchiness or stripping that tends to happen when spraying metal flake if you shoot the paint too close or your pattern is not quite right.
And yes like Skillz said make sure you buy a quality water catch for your compressor so water doesn't leak out and ruin a paint job. Also a good buy is a air pressure valve to put on the bottom of your gun, often called a cheater gauge so you can see and regulate the air pressure right at the gun.
Other than that I can't think of anything that hasn't already been mentioned and I know some of it already has, but can't hurt to hear it again.