Keep your right shoulder all the way down.
That's it. Period. This doesn't mean to keep your right elbow any lower - just your shoulder. It might not feel like the most natural approach at first, but I guarantee immediate results if you practice this way.
As a caveat, nothing worth having comes easy. So continue to improve everything else about your chords. Move organically. Involve your whole arm. Keep your body frame intact, or even use contrary motion (don't sway with the arm / instrument too much). Look at yourself in the mirror. If you look retarded or sound like a suzuki student, you're doing something wrong. Stop, reset, and try something new.