Often use games to incorporate the basic skills into your practice. Shadow drill frequently. Kids need to learn to control their own bodies before they can control someone else. Plus, everyone in the room is drilling intensely, simultaneously, rather than half of the guys being partners. Shadow drilling is fun for kids and good conditioning.
Kids use their imagination well.
This can help you lead into teaching visualization skills. Kids are never to young to dream about becoming a champion. Be enthusiastic and give positive feedback frequently. Kids need your leadership and guidance and thrive on positive feedback when they do something well. Also, give parents positive feedback if their child is doing well.