In my book, "On the Other Hand', is call the tilt the 'magic position in your stance'. Pretty strong words to be sure. What the tilt is and what is does is explained here to you.
At address (for lefties) our left hand grips the club below the right hand. Since the left hand is several inches lower than the right, the left shoulder should be lower than the right shoulder too. The spine is 'tilted' back about 15 degrees and the head is pulled back behind the ball.
Every tour pro in the world sets up with their head behind the ball. Most amateurs I see try to get their shoulders level with one another and that' impossible. The tilt puts your body in the correct position with your head back. Now, since your head is already behind the ball some it'll be easier to turn your shoulders behind the ball. On the other side of the coin, how can your turn your right shoulder behind the ball is your head is in front of the ball?
The tilt also squares your shoulders up so they're parallel to the target line which will eliminate many pulls, slices and over the top shots you may have experienced. If you tilt more you'll turn more and get more power and accuracy.
