Let’s start with balance, the basis of everything. If you move back on your heels or forward on your toes during the swing, your hands and body will try to compensate in some way to get the club head to the ball. That will change all kinds of things in your swing for the worse. You can’t fix any other swing flaw until you swing in balance. When you want to improve, you need to start by doing something harder than your desired end result. Swinging a club while standing on the foam log is a lot harder than swinging with your feet on the ground. If you can keep in balance on the log, you can do it on the ground.