Everything said is very good, all i wanted to do is add what is helping me with my flat backswing....i use a David Leadbetter image of making practice swings in my correct posture with my tailbone gently touching a wall behind me. Don't let the club hit the wall as you complete the backswing...you have to be more upright in order to do this and it is a good image that i use on the course as well! hope it helps you too!