If you are ambitious enough to repaint your car yourself, the first step is to prepare the surface for the application of primer and paint. Proper preparation will ensure adequate adhesion of a new coat of paint. There are many ways that professionals remove gloss car paint, including sandblasting, chemical stripping and acid dunking. For a do-it-yourself project, however, sanding is your best bet.
Pry off any trim from the auto body with a screwdriver.
Scrape any adhesive residue, pinstriping, decals, stickers and any other stuck-on gunk with a razor blade.
Wash the car with solvent-based automotive cleaner and degreaser to ensure all grease, residue and build-up are removed.
Rough-sand the entire car, using a dual-action sander with 80- to 100-grit sandpaper. Work the sander in circular motions, applying medium pressure. It is not necessary to remove the paint all the way to the bare metal to repaint; just remove the gloss finish. Use an emery cloth to get into nooks and crannies that the sander can't reach.
Remove the coarser scratches from the initial sanding by re-sanding with 180- to 220-grit sandpaper.
Sand with 320- to 400-grit sandpaper until you achieve a dull, but smooth surface.
Wipe down the entire car with mineral spirits, using a rag, to prepare for priming and remove sanding dust.
It is also a good idea to remove all fixtures that you are capable of removing. This includes door handles, the antenna, headlights and bumpers. If you don't have a dual-action sander, use a sanding block or sand by hand.