Needing a fast breakdown of advice for painting my truck

I am painting my Mazda... I have almost all the body work done.. and am going to go out and get a gallon of paint and some primer... Is there anything else i am needing to buy?( paint wise ) .. I was just wondering if anyone out there could give me a quick lesson on PREPING AND PAINTING and getting it done looking half way decent.. this is my first time so it's going to be kind of experimenting.. any help would be cool