Here's my super short science lesson on how to feel less hungry.

It's a little over-generalized but it's mostly true.
-Out of the 3 macronutrients (carbohydrate, protein, and fat) the protein reduces your hunger the most.
-Fat makes it take longer to feel hungry again, because it slows down the food leaving your stomach (and having food in your stomach is one of the things that tells your body it's not hungry).
-Fiber also slows the emptying of your stomach.
-Carbohydrates other than fiber don't do much for preventing hunger, but they do give you energy. However, the faster the spike in energy, the harder you'll "crash" after and start wanting more food.
-Protein and fiber both reduce how quickly your body absorbs carbohydrates, so you get a nice slow release of energy.
So based on that:
eat lots of protein and lots of fiber. Don't be afraid of fat, but don't go overboard because it has more calories than the other two. Limit the carbohydrates somewhat and spread them out throughout the day, always eating them along with foods high in protein/fiber. Don't eat sugar, soda, fruit juice, or other things that will spike your blood sugar super quickly.