Motivation is a key to succeed as a whole, especially for places like a busy restaurant. It's actually not an easy task to motivate the staff. You should think about it before an interview and based on your previous experiences come with a sort of a plan. However, if there's nothing on your mind, you can tell that you will use some team building activities, motivational bonuses as well as try to create a friendly environment, in order to keep the staff motivated and happy about being there.