Be aware that there's significant research that extrinsic motivators crowd out intrinsic ones. Essentially, they increase total motivation at the cost of sometimes reducing intrinsic motivation, which in turn creates a reliance on the extrinsic motivators. A good book on the subject is Punished by Rewards: The Trouble With Gold Stars, but if you do decide to read the book, be aware that the author is biased towards self-determination theory.