Ah, alignment. The simplest part of the set-up, except when our students don’t listen and implement our suggestions.
Using an intermediate target for alignment of the clubface is critical. So placing the club behind the ball BEFORE address, with the “eye” of the center of the club pointing “through” the ball and at a close (less than 12 inches) target in line with the flag: a specific blade of grass, divot, etc., is the key. Then building one’s stance around the clubface to take the address position, guarantees that the player is aligned correctly.
After all, the clubface is what strikes the ball. It had better be in the proper spot, or the entire set-up is flawed.
I equate this with shooting billiards or a firing a long gun. Imagine standing astride in these pursuits, and trying to tell where you are aimed. It’s nearly impossible to know where the cue/gun is really pointing. And using this analogy with your students is a great way to get them to understand.
I can’t count how many of my students seem to accept and implement this system in our sessions, only to see them a short time later not doing it! It needs to be emphasized in your sessions and play lessons so that they begin to see the value.