Drink lots of water every day - it'll keep you hydrated, and keep you mistaking thirst for hunger, which lots of people do. Eat plenty of fruits and vegetables (which I wish I could, but am allergic to so many of them now ), and one thing I read recently was eating an orange is better than drinking the equivalent orange juice, in that you'll feel more full, and you still get the vitamins and more of the fiber than you'd get from the juice.