goodbyebird posting in sun_salutation
Just wanted to share this excellent write-up on downward facing dog for beginners. I've had some issues with this pose myself, and this article gave me a lot of great advice on how to approach this pose and what adjustments I might have to make.
Take a look at the eyes of your elbows (the insides or creases of the elbows). Let each elbow eye face the opposite corner of the mat. So your right elbow eye faces the left corner of the mat, and the left elbow eye faces the right corner. You probably will have to rotate your upper arms to accomplish this, but let your hands stay connected to the mat.
To feel this external rotation in your upper arms, come out of the pose for a moment, and bring your arms out to your sides at shoulder height, like an airplane. Let your palms and the eyes of your elbows face the ceiling. Now flip your hands over so your palms face the floor, but the elbow eyes still face the ceiling. This is the rotation of the arms we’re looking for in down dog. Now come back to the mat, and re-setup your hands. Point your elbow eyes to the opposite corners of the mat by externally rotating your upper arms. Notice how that broadens the collarbones and draws the shoulderblades down the back.