A motivational tool or incentive is something used to excite a child into action!
Students need to know that they are important and that God has placed Mom and Dad in the position and responsibility of training and guiding their lives. They need to know that they are loved and yet disciplined. Motivation redirects the action towards the goal you have in mind. Your goal may be:
1) Change an undesirable habit.
2) Give encouragement for a success achieved. or
3) Passing on a reward.
Sometimes it might be to lighten the load of a disheartened child. Here’s an idea for the month, ... it might seem crazy, beyond reason, or ridiculous but try it sometime!

1
Try ringing a bell (right in the middle of class) once a day or week, just to surprise the class, in order to have a game or sing a song!

2
Try having a ‘Crazy Day’ where you can dress in a crazy fashion ... within reason! Or, allow the class to dress up Mom (the teacher!) in a crazy way, ... again within reason! (Example: teacher wears a winter coat in class) Set limits.