1) Pass out the 'Least you need to Learn' the week before so folks have a good general idea of the game mechanics.
In my experience, most people don't do their homework.
The best suggestion is already given - teach it on a 1-1 basis.
Another thing I played around with is play as a guide to the other player. That is, play a cooperative game where your victory requirements aren't important, and you are successful if the other player is successful. This should give you ample opportunity to play (in some cases sacrifice yourself to make sure the learning process doesn't come to a vicious end) and teach at the same time.