I think the greatest thing to draw new people in is to explain that there are actually rules to the games. Most people have the perception that pinball is just keeping the ball in play, and that the longer you do that, the higher your score will be.
It's surprising to most people that games have complex rule sets. Once people start to understand and follow the lights, lock balls, increase multipliers etc etc, ALL games start to have more appeal.
I find, just a few suggestions about what to shoot for goes a long way. The number of times I've heard, "Wait, you're actually AIMING for certain things??!" Is astounding to me.
I've been having mostly non pinheads over a lot lately. Everybody is having a blast. We've been playing their 3 combined scores against my one. It's pretty fun actually.
I've got one on the hunt for a SM now. That's progress!