Use a folded blanket or sticky mat to pad your head and forearms. Kneel on the floor. Lace your fingers together and set the forearms on the floor, elbows at shoulder width. Roll the upper arms slightly outward, but press the inner wrists firmly into the floor. Set the crown of your head on the floor. If you are just beginning to practice this pose, press the bases of your palms together and snuggle the back of your head against the clasped hands. More experienced students can open their hands and place the back of the head into the open palms.
Inhale and lift your knees off the floor. Carefully walk your feet closer to your elbows, heels elevated. Actively lift through the top thighs, forming an inverted "V." Firm the shoulder blades against your back and lift them toward the tailbone so the front torso stays as long as possible. This should help prevent the weight of the shoulders collapsing onto your neck and head.
Exhale and lift your feet away from the floor. Take both feet up at the same time, even if it means bending your knees and hopping lightly off the floor. As the legs (or thighs, if your knees are bent) rise to perpendicular to the floor, firm the tailbone against the back of the pelvis. Turn the upper thighs in slightly, and actively press the heels toward the ceiling (straightening the knees if you bent them to come up). The center of the arches should align over the center of the pelvis, which in turn should align over the crown of the head.
Firm the outer arms inward, and soften the fingers. Continue to press the shoulder blades against the back, widen them, and draw them toward the tailbone. Keep the weight evenly balanced on the two forearms. It's also essential that your tailbone continues to lift upward toward the heels. Once the backs of the legs are fully lengthened through the heels, maintain that length and press up through the balls of the big toes so the inner legs are slightly longer than the outer.
As a beginning practitioner stay for 10 seconds. Gradually add 5 to 10 seconds onto your stay every day or so until you can comfortably hold the pose for 3 minutes. Then continue for 3 minutes each day for a week or two, until you feel relatively comfortable in the pose. Again gradually add 5 to 10 seconds onto your stay every day or so until you can comfortably hold the pose for 5 minutes. Come down with an exhalation, without losing the lift of the shoulder blades, with both feet touching the floor at the same time.