What to do before the guests arrive.
When hosting a dinner party, your first step should be preparing or refining your menu. While it is your party and you are perfectly entitled to serve what you wish, the objective is to make the evening comfortable and enjoyable for your guests.
You should plan on providing all food and drinks for your guests, unless you have very close friends who really wish to help out. As host, your goal is to provide your guests with a lovely, fun, interesting, and carefree evening, and the guests' primary duties are to show up and have a good time. You should find out if any of your guests have dietary restrictions, and make plans to accommodate them as much as possible. It's not that you have to be a short-order cook and provide each person with a different dish, but make sure at least part of the meal will be tasty and satisfying to all of your guests. If you have mostly dedicated carnivores plus a vegetarian or two, make sure that you've got enough meatless options to make up a good meal, and it's also nice to enquire if your vegetarian guests would be upset or offended if you served meat.
Set the table before guests arrive. You might even want to do this the day before to save yourself time. You may set the table as formally or casually as you like, but do not use disposable dishes, flatware, glasses or napkins unless it is a picnic in the park. Everyone should have cloth napkins; they are not expensive and they are more environmentally friendly – simply throw them in with the rest of the laundry after each use. A tablecloth is a nice touch, as is a vase of low flowers and unscented candles on the table (just make sure the guests can still see one another). If you want to make the party more formal, put out silverware for each course. But don't feel that you have to be terribly fancy as sometimes a one-plate home-cooked meal is just fine.