Wolf was an older potty trainer, but we used single m&m's as rewards. (Sugar is about the best source of motivation for him.) I never made him try to use the potty, just said if he used the potty rather than his diaper he'd get an m&m. Then once he was staying dry it was if you keep dry all day you get a treat. At that point we started forgetting about it and every so often he would ask for his treat, but it just died out on it's own accord.