Attempting to paint a car by yourself as a non-professional used to be considered a wild idea. There are so many variables to consider and so many problems that can arise. Thankfully, this modern era provides the "do it yourself" fan all of the resources to paint a car that a person could need. Several paint companies make kits that provide all of the supplies needed for an entire DIY auto painting job.
The car's old paint must be sanded down thoroughly. Taking it to bare metal is not a necessity, although it does help. Once the car is sanded, body filler must be added to any dented or rusted out areas. This helps to smooth out the car back to it's original shape. Most fillers can be sanded down relatively easily. It does not have to be perfect the first time, which provides room for error.
The primer coat is the next step. Two to three coats of primer ensures that the paint will adhere well to the vehicle. It is a good idea to wet sand the car in between coats of primer to make sure that the surface is smooth. Once all of the primer is finished, it's time to spray the actual color or "base coat".
The base coat needs several coats to give it a good visual depth. As with the primer coats, the base coats need to be wet sanded to avoid "orange peel" or wrinkling of the paint. Many professionals that do custom work will do "candy" paint jobs, which refers to a silver metallic base coat sprayed with a translucent color over the top to give an extreme depth and shine. This is not recommended for beginners though, as it can be very difficult to touch up if not sprayed perfectly the first time.
Finally a clear coat should be sprayed over everything else. The purpose of a clear coat is for protection of the paint as well and a final touch of gloss and depth. Clear coats can prove to be tricky to lay down because of how transparent they are. As with the other coats, the clear coat needs to be wet sanded. This is an extremely important last step.If all of these suggestions are followed, a good quality paint job will be made. It's always a good idea to practice on test panels of metal to get used to spraying professional paint. There is no such thing as too much practice before beginning a car painting project.