Before aiming your AB at a model, play with varying paint consistencies, varying air pressures, (thinner paint consistencies require lower air pressures, and vice versa), and distance from AB to model. Keep your AB in motion - don't stop somewhere for more coverage. This will cause pooling, or runs. Wait until the first coat has dried then give a second coat. Under optimum conditions, the paint should start drying within minutes. If you're getting a grainy surface you're probably too far from the surface. Get a moisture trap for the air hose. Practice a lot first on older kits, or scrap. Always clean out your AB thoroughly at the end of every session. Other members will give you lots more tips. Sounds like a lot of work, but once you've mastered the AB, you'll never want to go back to paint brush!