Oh, and the advice I received and passed to Chris was draw a good amount of thick smoke (the thicker the smoke the easier it is) and then hold your mouth like you're trying to close your it around a baseball, leaving a very small hole in your lips. Then just kinda flick your tongue and/or more your jaw just the slightest amount and it should send a tiny puff of smoke out and if you were holding your lips right a ring should form. The mouth movement is the trickiest part of it for me. The best bit of advice is DO NOT BLOW any air!!!! All that will do, even with the tiniest movement of air I've found, is blow smoke out of your mouth.

But don't get me wrong. I only recently got 'em myself so I'm far from an expert. That's just how I was told and then worked it out.