I can't say this enough: don't wait until you're an expert to start teaching others!
You see, I started a meetup group (meetup.com/LearnToCodeLA/) and ran our first workshop this weekend! What a rush! I've never taught a class or anything remotely close to it before, and because I'm completely crazy, I decided to organize and run a computer programming workshop for 35 people! I thought it would be a disaster, but it far exceeded everyone's (admittedly low) expectations, including my own. :)
That said, even though some people thrived on the open-ended nature of this learning experiment, others were definitely a bit lost. I have a lot to learn about learning -- and especially about teaching.
So, to all my genius Google+ friends: got any advice for a newbie? :)