The most important thing to remember when entertaining—whether for two, 20 or 200—is that people want to have a good time, especially at holiday parties. All you have to do is prime the environment and they'll relax and have fun on their own. I've seen so many hostesses deflate over a sunken soufflé only to find that people ate it anyway!
Take the stress out of your evening by remembering that only you notice when something doesn't go according to plan. Don't let them see you sweat, and no one will be any the wiser. And when all else fails, pizza and boxed wine work wonders.
My mother and I are both terrible procrastinators, so anything that gets served at our holiday parties either was made long in advance and frozen (like our baklava) or was whipped up in a jiffy that afternoon (like our smoked salmon canapés with dill crème fraîche on toast points). We don't spend a lot of time fussing around with finger foods that take hours to create and seconds to demolish. Our staples our finger-lickin' good, usually pretty healthy (nothing deep-fried or artificial, though we make some exceptions for holiday favorites, like eggnog) and easy. The most important thing is that our guests have variety and abundance—though not so much to make them skip the main meal if there is one.
Another key factor is making sure that guests can serve themselves drinks. This saves us so much time when we're worrying about getting food passed around and allows people to feel at home, which loosens the crowd up. The rum punch doesn't hurt, either. I love the aesthetic of a gorgeous punch bowl filled with red liquid, and it's easy to make in bulk and have people serve themselves. Even better, if you whip up a specialty drink like this, you don't need to provide a full bar. This is especially nice when throwing a party in a cramped space or on a tight budget. Of course, it's always good to have wine, beer, water and a nonalcoholic cocktail on hand.