| I just did a wheel on my Focus ST and I did the following:
1 - Cleaned Wheel with white spirit
2 - Used Evo-stik Hard & Fast Metal Epoxy Putty(halfords) to fill the scrapes (wish I hadn't put so much on as it takes some sanding down, even with 200grit).
3 - Sprayed 3 coates of Hi-Build grey primer (leaving 15mins between coats then left for 24 hours)
4 - Sanded using 800/12000 grit Wet and Dry (halfords assorted pack) and cleaned again with white spirit.
Tip: Take the extra time at this stage as for best results the primer needs to be as smooth as glass!
5 - Sprayed 3 coates of MG Rover Sparkle silver (was a good match for ST wheel). I left the paint 24 hours but then didn't sand this down (this gives depth to the metallic paint according to the paint can...I think it did)
6 - Sprayed 4-5 coats of lacquer and 1600 grit wet sanded and finished with a polish with T-Cut rapid scratch remover to remove any laucqer run/overspray.
There's probably a few techniques, but that's the way I did it and I'm happy with the result!  | 
