My plan is to eat very light before the big meal - a cup of nonfat yogurt & an apple - and drink lots of water. I am on the WW program, so I'll be counting those points and planning what I'll eat before I fill my plate.
I really have to watch portions and make trade-offs. For instance, a plain sweet potato will satisfy me just as well as sweet potato casserole. That saves more points for the pumpkin pie, which I definitely plan to have - it's one of my favorites.
Also, I make lower point/calorie/fat versions of my favorites such as pumpkin pie and go for plain, non-seasoned vegetables instead of casseroles for the most part.