Set the trail wrist to 'bullseye away' at the top
Craig Hanson offers a backswing checkpoint he calls 'bullseye down, bullseye away': the trail (right) hand points back as if telling someone to stop, with roughly a 45-50 degree angle in the back of the trail wrist. He says this keeps the shoulders down and lets you release the club more under. Fanning the face open coming down instead leaves an open face you have to roll over and pull everything back, which he calls hard to repeat.
Channel: CraigHansonGolf
Watch official source at 1:36