Applying pressure into the ground is one of the important facets of maximising power. Many golfers lift their heels off the ground on the backswing which reduces the chance of generating sufficient club head speed. This is a simple drill i use with clients, you lift your left heel off the ground and the toes on your right foot. With this action, to initiate the downswing you have to plant your left heel into the ground to start transition, the left foot moves first then the weight moves from the heel on the right foot into the toe. This moves allows pressure to be applied into the ground and translates into more club head speed with driver.