I've read a lot of golf books, and have noticed a few consistencies between several of them. There are just some things that nearly every golf instructor/professional believes in.
One of these things is the slow motion swing.
Specifically, I read about this practice exercise in Every Shot Must Have a Purpose AND Harvey Penick's Little Red Book.
I've implemented this into my own golf game, and it has definitely improved my muscle memory, and my ability to ingrain different swing positions quickly.
To do this practice exercise, take a club (I use a 5 iron), and put a ball on the ground in front of you. Now take the club back as slow as you possibly can, still looking at the ball as if you were hitting a real shot. During this ultra slow swing, be aware of the different feels, and key positions in the swing.
I generally do this 5 or 6 times if I am trying to achieve a different position in my golf swing. It takes some patience and discipline, but if done correctly, it can do wonders for your golf swing!