Arrive on time and set up immediately. By union rules, you have 18 minutes to prepare. Find out the ready time for your specific make-up and the estimated time allotted. Ask what make-up colors are permissible. Upon completion of your make-up, check your performer in daylight.
Natural light is a better gauge than most make-up stations.
Follow through with your characters on the set. Be attentive, and watch your people like you would a major star. Thoroughly clean up your performer and assist with others. A little initiative is never forgotten. Wrap out in a timely fashion.