One of the challenges that comes with understanding swing plane is that you can't see it when you swing. With the help of a simple training aid, you can reinforce the feeling of the club matching your shoulder plane without having to use video.
Go to your local hardware store and have a piece of 8-inch-diameter plastic tubing cut to three feet. Holding the tube over your entire right arm, down the grip and over the top half of the shaft, make some right-handed practice swings. The tube will help you feel the club going behind you, but in the proper position relative to your shoulders.
1. One-planers often swing back too flat. Use a piece of construction tubing to link your shoulder, arm and shaft positions.
2. The tube will help you feel your arm behind you, but in position to come back to the ball on the correct plane.