In the golf swing, it is important that we use our spine as a rotational axis. Amateurs struggle to maintain their initial posture at setup.
During the swing, you may be lifting or lowering your spine angle; you may even have a lateral sway in which the spine gets too far ahead or behind of the golf ball. These are all characteristics of an improper pivot and will make it very difficult to create a consistent golf swing.
To help with this we recommend trying the club across the chest drill as shown by Swing-U instructor Ryan Rustand.
Setup in the posture you would for a normal golf shot. While maintaining your posture, bring the golf club up and hold it across your chest. Be sure that the grip end is on the lead shoulder.
Rotate back to the top of the swing and through. Focus on trying it point the butt end of the grip just ahead of the golf ball. Do your best to keep the initial spine angle you had created at setup all the way from the start of the swing to the impact position.