I always start out with (depending on how bad the scratch is) 1000, 1500, or 2000 grit sandpaper and wetsand the area. If you start with 1000, go to 1500 next, then 2000, or if you start with 1500, go to 2000 next. You get the idea. Some people actually work up to a 3000 grit sandpaper (I can't find any in my area). Then use a wool pad to apply and buff a heavy cut compound, get a new wool pad (or clean your pad) and apply and buff medium cut cleaner. I then switch to a foam pad and apply either a swirl remover or a fine cut glaze. Then I usually use a microfiber cloth (or old shirt) to apply some Nu Finish car polish and either wipe it off with the shirt or buff it with a foam pad. Then I would wash the car with dish washing liquid (get's rid of any left over residue and shows any spots that need more work). If you see any spots that need more work, start at the medium cut compound step, or swirl remover and work your way to washing again. Then apply cleaner wax, then regular wax of your choice.