Start out small, allow for many mistakes and repeat the rules a lot. In fact the first time should probably be about them creating their chars, unless you're doing pregens. Let them come up with ideas, ask leading questions like, how does your char know his/her char? How did he/she end up meeting? And introduce the World in small packages. If they ask questions, great, if not, try to answer the questions you would have. But once again, keep the text to a minimum, start out by learning mostly through doing.
Try to accomodate them and not get mad if they fool around, but don't let it go overboard, you should definately schedule one or more pauses in, if it seems needed. If there's time left to play, try to end it on a Cliff-hanger.
And finally, after the session, ask them for input.
I'll keep a look out for articles on this subject and post them as well.