Took the x3 for one year service and bought the BMW paint kit (it's primer and paint), matching to the color code

Just wondered if anybody had any tips before i do this...The service tech said I didn't need to sand down before I did it, but I'm not sure they give the best advice.

Has anybody done their own touch up work? This are mostly minor nicks and scrapes that are pretty much part of living in New York City/parking in a garage where service attendants park the car.

Thanks