Its not like you're on hand to teach people how to play.
So, why don't we?
Tossing out a few ideas.
I've been playing these kind of games since 1976, so I've read a lot of rulebooks in my time. Every time I had a new player to be introduced into one of my D&D games, I would hand him/her the DM's guide and have them read the "example of play" mini-adventure that was in there. You know the one; it reads like an actual script. GM says this, John-player responds, Mary-player asks question, etc.
I've found that it provides not only an example of the rules, but an example of the flavor of how these RPG's are conducted. You can almost see the light bulb go on, at times, above the heads of new players. They relax as they understand more of what will be expected of them.
Everyone will have their own style in the game, to be sure, and no two will be exactly alike, but to have some examples of interesting, exciting, even comical situations and the responses by the GM might do well to prime the pump and excite some imaginations. While there is no one right way to run a game, there are unfortunately a few wrong ways; and a game where no one is having fun is an example of a wrong way.
You're right. We can't be there to teach all the players how to play or GM.
But we can help them by providing some examples of how to overcome some common roadblocks; if not in the printed rulebook, then perhaps here in the discussion boards?