Two of my little tricks...
1) Before every meal either drink an 8oz glass of V8 juice (if you like it). It fills me up and counts for 3 servings of veggies. Or...eat a nice salad...or both.
2) If I do have a snack, I'll put a small handfull of chips in a bowl or paper cup and put the bag back in the pantry. This way, when the bowl is empty, they're gone. As opposed to just sitting on the sofa with the bag in my lap, and eating half the bag.