Opening the book…
A stalling body forces the hands to save the shot, and hand-timed clubfaces are the least repeatable thing in golf — that's where the two-way miss lives. Continuous rotation keeps the handle moving forward, which keeps loft down and the face stable through the strike. It also protects your lead wrist and lead side from the flip that produces thin, high, weak irons.
Feel the buttons on your shirt rotating past the ball and keep rotating until your chest points at or left of the target. Rehearse it slowly: swing to a waist-high finish with the chest fully turned and the hands still in front of it, then repeat at speed. On video, look for the clubhead never passing the hands before the ball is gone.
On deliberate high, soft shots and some greenside pitches you release more loft with the hands and turn less. Physical limits — a bad hip or knee that won't accept load — may cap how far you can rotate; turn as far as you can and shorten the swing to match.