I think everybody is agreed that on the downswing the shoulders are supposed to unwind on a shallow plane that is at right angles to the spine and that the club is supposed to come down in a steeper plane that goes from the ball through the shoulders.

I can't do this. I can only seem to think of one thing at a time. Is there a drill of some kind that will help me? All the golf instruction books discuss the two planes but don't offer any advice -- as if the writers think nobody has trouble with this.