I cannot count the amount of times, I have had to remind my students that the ball just gets in the way of the swing. In order to help them understand this, I tell them to practice their swing without a ball. This allows them to focus on feeling the club and then following it to complete the swing. If they can do this and appreciate what I am trying to teach them, they will improve.
Recently one of my student's shared an article that was posted in Golf Digest back in February 2012 by Managing Editor Roger Shiffman that echoed the benefits of practicing your swing without a ball. It is a great read.