From garyknight via Flickr
I should have thought about KISS so many years ago. Keeping it simple is the only way to make it through with you sanity intact at the end of the day. If you have having ten people over you don't need three meat choices unless of course you just have tons of time, money, and space on your hands. So let's see how much we need.
Appetizers - If you are doing a dinner then 3-4 pieces per person. If you are only doing appetizers then 6-8 pieces per person per hour of the party. You certainly do not have to make individual appetizers, I usually don't. On Thanksgiving I usually just sit a veggie tray out. This gives everyone something to snack on without it being too filling. It also can stay for dinner for those who want extra veggies. For a Mexican dinner I'll make a queso but not a whole slow cooker full. The rule of thumb with dips is 1 oz of dip and 2 oz of chips for person.
Main Dish - Unless you are throwing a wedding reception there really isn't a need for multiple choices of main dishes. If you always fix ham and turkey for the holidays by all means continue doing so, you don't have to kill the tradition. If you are having friends and family over for lasagna then you don't need to serve several kinds of it. Make your lasagna, your family will love it. The big secret here is to make the main dish gluten-free and not off the wall. Enchiladas made with crepes (haven't tried but heard you can) might be too different for most people. A roast, meatloaf, or even pasta are easy gluten-free meals that everyone will enjoy. If cost is an issue then don't have people over for pasta make something else. The one exception to this rule would be if you had a vegetarian or vegan in the group. If there is an easy way to give them the same main dish DO IT. My father-in-law is a vegetarian, I don't make him a faux turkey on Thanksgiving but when we have kabobs the veggies are marinated separately and he gets three instead of two. Now how much do we need? 3/4 of a pound of 12 oz per person if we are doing meat as the main dish, i.e. steak, chops, chicken breast. If you are serving a lot of sides you can drop it to 1/2 of a pound per person. If it is going into something like stir-fry or pasta sauce you can cut it down to 1/3 of a pound per person.
Side Dishes - This one is hard because when it comes to holidays it seems we all have a list that we must have or it's not ___________________. I'm there with you. Make smaller portions of them. Think 1/2 cup as a serving when planning. If you are serving more than four you could get buy with a 1/3 of a cup except for potatoes. Potatoes you should plan on a little over a half of a cup and keep it there. I make more because I am a potato lover, I'll leave the main dish on my plate to finish a good potato dish.
Dessert - One slice of pie, cake, tart ect per person for the end of a meal. If you are going to have a dessert only then, this is perfect after an evening at a concert or play, I usually go with two if it is a small group or three if it a medium size group.
Drinks - 16 oz of non-alcoholic drinks per hour and 2 alcoholic drinks per hour per guest and have water available.
That's it you've got the basics now well start in on the appetizers.