There is a good thread over at ArcheryTalk about the experiences of an archer learning how to shoo t back tension. It’s an interesting read and has some good experiences to learn from. The thing I remember most about learning to shoot back tension was having the hinge too loose and punching my self in the face, splitting my lip and nearly knocking myself out.
I finally figured out how to relax the draw arm while anchored. That is probably the biggest thing that I needed to learn. And the results were huge. While only aiming at a predominantly blank target bale, I kept my groups tight, only using a balloon remnant (from a JOAD Class) as a target point of reference.