I went to a lovely yoga class at West Asheville Yoga the other day and got a great tip from teacher Amah Mitchell on side angle pose.
"Engage your back glute" is a fairly common cue in poses like Warrior I and II, but not something you often hear in side angle. So I gave my butt a squeeze and was surprised how dramatically it changed the pose.
It takes you deeper, brings your pelvis into a more neutral position in the transverse plane and allows you to lengthen through both side bodies instead of collapsing down onto your arm. This, in turn, puts your neck and even your shoulder in better alignment.
Give it a shot the next time you find yourself in this pose.