Step 3: Sand!
Sanding the car before painting it is like...opening a bank account before making a deposit. Ya just gotta do it. First, use strong soap, wax and grease remover, or whatever you have lying around to clean the heck out of the paint. Then sand it with 300 or 400 grit paper.
For difficult areas, you may want to get some abrasive foam or scouring material that conforms better than regular sand paper. The point is to completely eliminate the shininess of the finish, and get past the clear coat. You don't want to sand down to bare metal, there's no point.