1. Don't spend too much time cleaning - just do a quick dust, vacuum - and stash the clutter behind closed doors. By dimming the lights and using candles, your guests won't see the dust bunnies under your sofa. I usually try to concentrate on the bathrooms - if they're clean, I'm happy!
2. Decorate simply. I don't spend any extra money or time on decorations other than what I already own.
3. Plan your menu in advance - and make sure you have all categories covered - salty, sweet, sour...crunchy, creamy, etc. I usually do finger food so my guests don't have to mess with silverware - and I use paper plates, so I don't have to wash too many dishes afterwards!
4. Set up some games on tables beforehand. At my house, we set up simple, easy games from our childhood (Operation, Kerplunk, Catch Phrase, Rock'em Sock'em Robots); the games are in different rooms, encouraging the guests to move about. We offer a "grand prize" at the end of the evening for everyone who participated in the games. The games encourage mingling by the guests, and gives them something to do - besides EAT!
5. Have Christmas music playing softly on all radios/stereos in the house.
6. Offer simple door prizes - I sack up some chocolates, candies, etc - and all guests go home with something. No one leaves my parties empty-handed!
7. Have something set up for the children to participate. At my house, it's the Wii - the kids love it. It keeps them entertained, and allows the adults to play their own games.
8. During the party, keep one eye on your kitchen/food/drink area, and the other eye on your guests. I try to have fun, but I keep an eye out for potential problems - i.e., running out of ice, no toilet paper in the bathroom, a guest who appears "shy"; etc.
9. Take photos during the party - or assign someone else the job. Then, the following year, I put a photo show/slide show on the TV of last year's photos. We have some great shots of the guests playing KerPlunk!
10. Have fun!!! Enjoy the party!