Ordering pizza also works pretty well. Make sure everyone chips in on the bill so you don't get screwed. Adding music to the environment helps to keep things interesting, even during setup and those awkward moments. When things are silent, LAN-party goers get bored and possibly sleepy. If you don't have a notebook or an extra PC for MP3s, use a boom-box or home entertainment center, if available.
Dedicated servers lead to less lag.
Without a dedicated server, someone has to host the games on the PC they play on, which leads to poor performance. This usually isn't a major consideration, but you never know. Crank the AC is available, or use fans, open windows, doors, etc. to clear out the hot air. Garages seem to be very good for this purpose if the weather permits. The smart guys just put wheels on their cases so they don't have to carry the heavy ass things all over the place.