For most players, there's a a tendency to rise up on the ball of your back foot at the start of the downswing, in the hope of adding speed and power. But when you jump up and forward like this, it disrupts your posture; your spine angle straightens, your shoulders come off plane and your hip tilt gets out of whack. Consistent impact? Forget about it. To nix the habit, imagine a plump grape under your back heel. As your transition into your downswing, squish the grape into the turf using everything you've got. By planting your right heel, you'll stabilize your posture. Now you can go at the ball as hard as you want, and beat it — and that grape — into a pulp.
Raising your back heel changes everything—none of it for the better. When you jump up and out in front of the ball, there's no way you can make consistent impact. I see this mistake with pros and amateurs alike.
When you squish a grape under your back heel, you'll stabilize your posture in the downswing and create a more consistent impact pattern. "Make some wine," I tell my students. It's a power move that works wonders.