Hi Rebecca! You post a great question. I struggle with feeling full so I can't wait to see if the other girls have any suggestions. My trainer always tells me to aim for protein. That protein keeps you feeling satisfied longer. Doesn't seem to be the case for me tho.

When I first started Weight Watchers, they told us that we generally eat the same 30 things consistently. So crack out those measuring cups and figure out what a serving size looks like! I've been doing it so long that I can now pretty much tell how much of a food item I've dished out. Anything involving recipes or eating out gets a bit tricky for me. If it's not something I'll have repeatedly then I do my best to break it down and estimate high.

I second what Sue suggested. It's important to learn what a serving size is for the foods you eat so that you can accurately track what you are eating. That means weighing and measuring until you have it down. It seems like a pain in the beginning but it's so worth it. Something I love for breakfast that keeps me full longer are the refrigerator oatmeals:
http://www.theyummylife.com/Refrigerator_Oatmeal

I make the blueberry maple flavor whenever I'm going to have a busy day and it's allowed me to skip lunch more than once because it's so filling and seems to provide steady energy. The banana cocoa flavor has been a great dessert substitute as well.

I think it boils down to what foods give you the most value - after you've been tracking for a while you'll figure out which foods keep you full longer, keep your energy level steady, and don't break the calorie bank.

I vote for protein + fiber, and a bunch of water. Keeps me way more full than anything with sugar or lots of carbs. There is a bar I really like - Quest bars. You can get them at GNC. Half of a bar is almost the exact nutritional equivalent of a Medifast meal (I don't do Medifast now but their meals all have the same nutritional profile and they make you feel full). It's a super healthy and filling snack!