Stay in your comfort zone. Only invite the number of people you feel comfortable with and that you can comfortably fit in your home.
Plan your menu well in advance. Offer variety ... 3 salads or veggies, 2 starchy side dishes and more than one meat option. People enjoy tasting several things but it also naturally takes care of food preferences and dislikes.
Do not feel that each recipe that you will serve should be scaled up to feed the number of guests you are inviting. For example, if 20 people will be coming, you do not need to put out 2 salads, 2 sides, 2 meats, and 2 desserts that each will serve 20 people ... you will be left with a lot of extra food. The great thing about offering a variety of choices is that most people will take a little of everything, so feel free to make only enough for approximately 1/2 to 2/3 the number of people. If a side dish casserole usually serves 8, simply double it, don't feel the need to triple it to cover the number 20. For meat, count on about 60 g or 2 oz (cooked) of each type you are serving per person. Large cuts of meat, such as a roast, turkey or ham work well or chicken breasts that can be cut in half.
Many recipes or parts of the recipe can be made in advance. Plan your menu and then make a to-do list of those things you can prepare 1-2 days ahead of time.
Be sure that your oven, refrigerator, and freezer will hold everything you need.
Move everything not needed for the party from the primary fridge to the basement fridge. This could include things such as condiments, leftovers or other food you know you won’t need for preparation or during the party.
Make use of re-sealable vegetable bags to keep salad greens, cut veggies, marinating meats, and even marinated salads until just before serving. Re-sealable bags stack nicely in the fridge and take up much less space than bowls.
Consider renting plates, glasses, flatware, and serving dishes. They are amazingly affordable and everything matches — especially nice for a more formal affair. You don’t even have to wash them to return them — just scrape and rinse them off.
Designate someone to greet guests with you and take wine, gifts, flowers, etc to a central area so you are free to make introductions and settle guests.
If you only have one fridge and will clearly need more space, ask neighbours or friends who live close by if you can "borrow" fridge or freezer space. Chances are they have a little spare room. Or borrow large coolers and buy some ice if it’s important that you have everything at your fingertips.
Have a plan for pets, preferably somewhere outside of the dining area.