Up your water intake. Drink a full glass BEFORE every meal.
Add fruit and veggies. They take up space on your plate and in your stomach, are GOOD FOR YOU, and the added fiber keeps you full longer. Don't just have them as a side. Incorporate them into the actual dish - be it a stir fry, some pasta, risotto, or even layered on a sandwich.
Low-fat or non-fat yogut - this is my favorite afternoon snack and packs a calcium/protein punch. Yoplait has a bajillion favors with only 100 calories, and no fat. Try Boston Cream Pie, Pineapple Upside Down Cake, or Lemon Cream Pie!