From Escape Development:
Reward charts are an excellent way of encouraging good behavior in children from three to eight. Reward charts focus on positive re-enforcement of behavior by giving constant feedback and a sense of achievement for the child. Set up your reward chart with your child by choosing the behavior you want to change or encourage. Add these tasks to the chart. Choose some short term rewards from a range of special treats, try and scale these rewards up as the amount of stars increases.