These arm balance videos shown generally include poses where one or both legs are positioned on the back of one or both arms, making it easier to balance on the hands. Also included, even though it breaks these rules, is mayurasana, where the belly rests on the upper arms.
For people who are relatively new to yoga and relatively new to the idea of balancing on their hands, here's a step-by-step introduction for getting your feet of the ground for crow pose... without jumping.
Do you really need to do crow pose with your eyes closed?
Not really. I usually demonstrate crow pose with the eyes closed to show how feel your weight shift from feet to hands, so that you know when you can lift your feet simply by feeling your connection with the ground.
Some tips for side crow pose (or "Bakasana"), including how to move into rotated flying splits (eka pada koundinyasana 2).
So that Eka Pada Koundinyasana (or flying splits) is a little bit easier to learn, here's a progression of exercises for learning the basics of this arm balancing yoga pose.
The following videos each include specific exercises for learning the basics of the astavakrasana arm balance.
A step-by-step look at mayurasana including preparatory actions for the spine, abs and shoulder blades.