Downward-Facing Dog

The way I teach beginners this one from kneeling on all fours: lift knees an inch off the floor, look down and push the mat as "far away" with your hands as you can, so your head dives between your arms, then with knees still bent, the LAST thing you do is try straighten the knees and pedal the feet, one by one. I find this helps them get a nice, long, flat back, which is more important initially than straight legs.