Know Your Danger Zones
If you know sitting in the kitchen is going to cause you to raid the pantry... leave the room. If lingering at the dinner table makes you long for dessert... vamoose!
For example, don't use the kitchen table for other activities like paying bills if you know you can't fight temptation. (The cookie jar always calls my name when I'm busy crunching numbers.)
Or, even better ... as soon as you've finished your meal, head outside and take a walk. Not only will it get your mind off of eating, you'll have the extra benefit of exercising!