These changes rotated the clubface so the toe pointed more toward the ground, correcting the shut position. A good tip if you hook the ball. A stronger grip will help eliminate your slice. Hogan's secret was a weak grip, the bane of slicers. First, when you let your arms rotate in the backswing, be careful not to overdo the move.
Most slicers allow the clubhead to move well behind their body.
Second, a weak grip is all too common among slicers, so rotate your left thumb to the right to create a stronger grip. Finally, make sure your left forearm and the back of your left hand are flat at the top of the swing. These changes will help you develop your own secret, that of the slice-free swing. A flat left wrist position will help a slicer square the clubface. Hogan's cupped left wrist position contributes to a slicer's problems.