Painting is not hard as long as you follow some simple steps. First, grab an inexpensive water trap for your compressor if you don't already have one - I paid like $5 from Tractor Supply for mine with a regulator. Probably not the best in the world but it works. Painting likes DRY air. Your gun will have instructions on what PSI to have the regulator set at. Make sure you pick up a bunch of paint strainers (paper funnels with screen in them) and a bundle of stirrers. Another thing to remember is your paint job is only as good as your prep. The more you massage the bodywork, the better the end result will be. If you have a garage, keep the door open so you don't get baked

. I don't and shoot mine outside on a warm, dry day after bug season is over. Trust me, insects LOVE fresh paint.
- Don't get your paint until the day you are painting and have them shake it really good before you leave the store (or if you get it at say Walmart, stir it really good, I use an old kitchen hand mixer).
- Wipe the entire thing down with a good degreaser\prep like PrepSol. I use shop rags because they don't give off lint.
- mix your paint one spray cup at a time, no exception. Paint starts to cure as soon as it hits the air so mixing a big batch is a big no-no. I use bunch of old margarine containers and some kitchen measuring cups from the dollar store. Use the strainers when pouring into the spray cup. Use a new strainer each time.
- Take your hand and put the pinky on the truck and the thumb on the spray nozzle of the gun. That is the distance you want to be from the truck at ALL TIMES. Spray from left to right, keeping that distance the entire time and the gun parallel to the truck surface. Start moving the gun a little before the panel you want to paint and then hit the trigger, reverse this at the end of the panel (let off the trigger at the edge of the panel but move your arm a little further). This keeps the paint even. Make the next pass in the other direction, overlapping the first one by about a third. The first coat you want to just be fogged on, not actually doing any real coverage. If it's a big section like the bed of a truck, WALK as you paint, don't stand in one place and swing your arm, you will get crappy quality. Once you have finished the panel you are on, move on to the next and work your way around the truck. By the time you get back to where you started, it's ready for the next coat (should be a little tacky). You can do the next coat(s) a little heavier until you are happy with the coverage. Remember, less is more. It's much easier to spray more paint on than to have to sand off runs later.
-clean the gun when done very well with thinner or spirits. A dirty gun is an unhappy gun.
This sounds harder than it really is. I recommend practicing on an old scrap of metal like a junk door or an old washing machine so you can get the hang of the process and play with the adjustments on the gun - one knob controls paint, one controls air and the nozzle can be rotated to fan either horizontally or vertically depending on the size and location of what you are painting. Too much air\not enough paint and it will go on 'dry' and be dull-looking. Too much paint, not enough air and it will spit and splatter and run.
I only use single stage paint - paint that doesn't need a clear coat and dries hard and shiny. Let the paint cure at least a day or two before taking it out on the road, paint dries as a 'skin' first and then from the inside out so it might seem 'dry' but is actually still kinda soft. This also depends on the paint. The Rustoleum stuff dries completely by morning, real auto paint takes a couple of days. Wait at least a few weeks before putting any wax on it.
The bluish bus we painted in a few hours. The Mustang was a couple of days affair because of the stripes and because black shows errors really well. The purple beetle was done in an hour.
Here's some before, during and after shots:
Keeping some Dodge content

that's my son's Dakota pulling it: