The pitch is on the way and you are starting your swing....

The front foot has landed as part of your load.  Try to land with the front foot on the toes first.  Your front heel will move to the ground as your back heel pops into the 'squish the bug' move, or 'lock and squash'.

The swing is underway and when you 'lock and squash' the front leg straightens while the back foot turns so the laces of the back shoe are now facing the pitcher. 

At this position, the back heel has popped to the sky. 

This move generates the power from feet to hips.

At the point of contact, notice the back elbow is close to the back side ribs.  The front arm is leading through the hitting zone. 

The head is tracking the ball to the point of contact. 

Front heel is down, back heel has popped to the sky.

Hands in a perfect palm to palm position.