1. It must be short and highlight one and only one action. The total length should be less than 500 words.
2. It should be frequent; once a week (I believe that once every two weeks to a month is better) on a regularly-scheduled basis.
3. It should have a call to action. Tell the recipient what you want them to do: come to the site to get something, come to a show, etc.
4. It should be forwardable. Ask your recipients to forward the email to someone they think will enjoy it.
5. It should have sharing functions embedded. Allow people to Tweet, add to a FB status.
6. Make it easy for people to unsubscribe.
George also states the following:
"Don’t worry about overwhelming people with email blasts. If people are unsubscribing, they’re likely non-value adding “fans” any way. Instead, focus on presenting real, timely, share-able value to your current fans so that they have a tool to help you gain new ones."This I don't buy. I think it's important NOT to overwhelm anyone, as you'll be perceived as a spammer. Emails are difficult to design well, and it's pretty difficult to keep coming up with pertinent info regularly, especially on a weekly basis. That's why I believe that it's both better for you and your fans if you have a longer period in between emails.
That being said, George's steps are right on. His post was more on psychographics and converting fans into customers, and is definitely worth checking out.
Check out my Big Picture blog for discussion on common music, engineering and production tips and tricks.