Good communication skills are a must. Our alliance uses Skype to chat with. I like Ventrilo myself but someone has to rent a server for that.

Spelling! Even with game mail a Host and Vice etc. should use an external program that has spell check to compose important messages and correct obvious grammar errors.

Last but not least get opinions from everyone you can on important matters (within reason). Some mere members may be smarter and more up to date on things than the "officers" in the game. Not everyone is as they appear Don't say "the Alliance" decided when it was just a few people who made the decision. No on likes to be taken for granted.