1. Keep It Simple. The last time I taught yoga to a group of kids, I stumbled all over myself trying to find the right words to explain the complex notion of namaste. "It means that we all have a little shining light inside of us that connects us to each other. When we say namaste, that little light is saying hello to the little light in other people around us." My explanation didn't make much sense, even to me. One little girl looked me right in the eye, hands folding into Anjali Mudra, and said, "Hello, Light." As it turns out, I was over-complicating a very simple idea. Yoga doesn't have to be so complicated. Just breathe and move, move and breathe ... It can be that simple. (Read about the whole experience here.)
2. Use Your Imagination. Why don't we spend more time imagining we're opening like butterflies when we practice Baddha Konasana (Bound Angle Pose) or flying like Superman in Virabhadrasana III (Warrior III Pose)? Yoga is a connection of our minds and our bodies, so why not connect our imaginations, too? On those days you feel your enthusiasm waning, use your imagination to come up with new, creative ways to look at the poses and you'll never get bored!
3. Just Do It. When children see someone try a pose that looks daunting they don't throw up their hands and say, "I could NEVER do that." They don't even think about it--they just try it and see what happens. And afterward, you can tell by the look on his little face that he KNOWS he nailed it, even if the reality wasn't exactly true to form. Kids might not be able to exactly mimic the physical part of the pose all the time, but they get the experience of it anyway because they're willing to try. And isn't that the whole point, anyway?
4. Don't Worry About What Others Think. Admit it. There are times when you check out the people around you in your yoga class. You might think, Her Downward Dog is SO much better than mine. Or, more likely, you think: Did he see me fall out of Tree Pose? Young kids don't do this. They're naturally confident in their abilities, and they don't care who's watching! Remember what that felt like? That's what this practice is supposed to feel like.
5. Have More Fun. This needs no explanation. Adults tend to take everything too seriously. Kids find the joy in everything (well, kids who are in a good mood, anyway)! Don't get bogged down in feelings of inadequacy, esoteric theories, or whatever else sucks the joy out of it for you. Practice because it's fun! You don't need any other reason.