Here are a few things that you can do while waiting for yoga class to begin:
1. meditate. don't get too concerned with whether or not you are doing it right... just close your eyes in a tall seat and observe your breath.
2. meet someone new. just turn to the nearest person... they will probably sense you looking at them and look back. smile big, like they are already your best friend. say, "hi, my name is ....." and stick out your hand for a shake. this builds community in your studio. this develops your compassion your presence and your connection to others.
3. neck stretches. turn to the left, turn to the right. tip to the left. tip to the right. turn to the left again and nod slowly, up and down. turn to the right and nod slowly. pausing in each position for 1-3 breaths. don't be in any hurry with this. get fascinated by sensation, strong or subtle.
4. go say "hi" to the teacher. i can't speak for every teacher, but i am here for you and i love it when you come to talk with me. when you come tell me your name, check in, and say hi... i am more likely to remember you later and connect with you in that class. come tell me your favorite yoga pose, or one that you are struggling with. let me know where you might want my eye in class. put in a request for a body part or pose you want addressed this class.
5. toe gymnastics. this simple self care act, a lot like a massage, may improve your balance and stability. I learned this from one of my teachers, Harvey Deutch and he has a great description here: http://www.redhawkpt.com/sites/default/files/Toe_Gymnastics.pdf
6. supta padangusthasana. a teacher one told me that this is one of the best things you can do for your body: grab a strap. lay on your back, knees bent, shoulders on floor. loop strap around right foot. lengthen both legs out. lifted leg need not be perpendicular to the floor. one hand on each end of the strap. shoulders get heavy and relaxed. breathe. both ends of the strap move to the right hand, left hand to left thigh or hip. with out lifting the left side of the sacrum, lower right leg to the right. breathe here. bring it back to center. switch hands: straps to left hand, right hand to right hip bone. with out letting the right side of the sacrum lift lower the leg to the left. it will not go far that is OK! breathe here. do it all on your left.