How should i reward my child when trying to get her to quit thumb-sucking?

Small rewards: Children respond to small incentives. You want to avoid doing something large because that makes the effort too cumbersome. A small sticker in a book for a block of time, like a morning without sucking, is appropriate. Add them up to get an action figure or another small but prized object, something that would take a week or so to get. After awhile if successful the child can "graduate.".

Rewards for good : Rewards for good behavior can be a simple as goods words and praise for good behavior. Most children like to keep their parents happy and do good. Try to stay away from candy. You can try bribes like a certain toy but try not to get in the habit of rewarding them for everything it is amazing how many parents tell their children they can get a toy after their doctor visit. Anyway. Good luck.