You can do a few things to help prevent your turkey breast from drying out. First, make sure you don't overcook it. Use a meat thermometer to check for doneness, and take the turkey out of the oven when it reaches an internal temperature of 165 degrees F. Second, try marinating the turkey breast overnight with olive oil, lemon juice, and herbs. This will help to keep it moist and flavorful. Be sure to also 'rest' the turkey out of the oven so the juices permeate it.