 To get and stay behind the ball, take your normal driver's stance, then move your right foot a step away from the target so your feet remain square to your target line, but wider apart. If you're a left-handed player, then you'd move your left foot of course. This foot adjustment places your head further behind the ball. Just set up in front of a mirror and shift your right foot and watch your head move a little further back of the ball where it needs to be.