One of the most common mistakes that I see golfers make is not keeping their arms in the proper relationship with their body when they turn. When you set up to the golf ball your arms are right in front of your body.
Common Arm Position Mistakes
When you turn you want to keep them in front of your body as you go back, out in front of your body as you get to the top, out in front of you as you come down and the same as you come through.
What I see golfers doing is either separating their arms too much from their body, becoming disconnected as we call it, or pulling their arms in, where they are disconnecting their right arm.
Ideally, when you pivot your body, your arms stay in the same relationship that you started with. Out in front of your body, keeping your arms out in front of your chest as you go back and as you come through. Maintaining the proper relationship with your hands, your arms and body is the key to a consistent golf swing.