Make a recital handout that covers everything you feel is important, including bowing and applause, what to do if there's a memory lapse, etc. Your recitalist may have to change into her uniform in your bathroom and leave before refreshments. Encourage the family to stay as late as possible, however, movement in the recital room is distracting to others, and their exit states quite eloquently that they do not think this recital merits their full attention. If at all possible, schedule the student in the spot appropriate for her if she is fairly skilled, rather than at the beginning of the program so she can leave early. Go the extra mile, but draw a line and stand by it firmly.
Piano is just as important as sports.
Before the recital begins greet each family and speak specifically to the recitalist. With children and teens, you might comment on how nice they look, but the gist of this pre-recital chat is to communicate support and confidence that the student will play beautifully. Each of these people should be complimented on the child's performance, and you should note how proud you are of their playing and their hard work. Praise the student again at the lesson following the recital. Sometimes a student will want to get involved in a post mortem of his playing during the recption.