I'm currently running 4 campaigns with about 10 players. How do I do it? Well, I create adventures for a continuous campaign set in Eberron. I first run the quest with my Tues group of four players. Then I run the same quest on Sat with another group of players. On Sunday I run selected adventures from Dungeon Mag. open to the public at my local retail store. Then, whenever I can, I run Mark of Heroes adventures.
I've also created a web-site (free) where I update my players on the upcoming adventures, allow them to "sound-off" at each other on my message board, and highlight questions or concerns that they have about the game. My real goal is to get several groups of GMs and Players listed on my site to allow the players a chance to meet other gaming groups.
I encourage everyone to check out my site. Give me some feed-back. If you like what I'm doing, copy it.
www.area153.freewebspace.com
Wow, you ought to get Starbucks or Jolt Cola to sponsor you!!
I'm lucky if I get one hour of game prep in a week!!