Appropriate age group(s):
Preschool and Younger
Elementary School

Description of stocking-stuffer idea:
Get a puzzle or make your own from a blank one you can get at craft stores. A more complicated one for older students, an easy one for younger. Agree to a reward or privilage the child wants. When the child demonstrates the wanted social skill or behavior you are trying to enforce, let them ad a puzzle piece or a number of agreed upon pieces. When the puzzle is complete, the reward is given.

Other comments or suggestions:
Make sure the child chooses the reward, it is more motivating. A hand made puzzle could be a project for you and your child to make together. It could say the name of the reward, etc.