Setup:  The hitter should be in an athletic position but relaxed.  The hitter's feet should be close to shoulder width apart with the back foot turned in slightly to promote a good hip turn and to stop any weight from creeping to the outside of the back foot.  The hands should be back towards the back shoulder with some space between the shoulder and the hands.  This is just a suggestion for the best possible position to get ready for the hitters load position.  In this picture Albert Pujols does a few things different in his set up.  His hands are above the shoulder and his feet are a little wider than shoulder width.  Each hitter will have some unique setups that feel comfortable to them and should not be changed unless their positions cause swing flaws.  During Albert's swing the hands drop to shoulder width in the load position. He also lifts the front foot and takes a very slight stride step that makes up for the wide stance.  

Load:  The hitter should begin his swing with a slight inward turn putting the weight  onto the back foot. This is a slight motion.  The hitter must not overdue the turn causing the hands to wrap the bat around the neck.  This motion is done with the timing of the pitch.  

Stride:  The hitter then begins his stride step.  The weight must stay back towards the inside of the back foot in this part of the swing.  The stride step should be a soft step with the big toe landing and with the foot staying closed.  This is done on every pitch no matter if the batter swings or takes a pitch.  A hitter can never practice this step enough.  The hips should not rotate with this step.  The hips and body must stay closed to the plate during this phase of the swing.  The shoulders and hands stay back towards the catcher getting that little extra stretch from the lower body.  The eyes and head stay steady but may move slightly forward with the motion of the stride.

Rotation:  Now the hitter is ready to power through the ball.  The stride foot plants to the ground which triggers the rotation of the hips.  The hands stay relaxed and a pull sensation is felt from the stretch between the lower body and upper body.  The batter does not consciously pull with the upper body.  The relaxed hands and the rotation of the hips will take care of the upper body.  The upper body is basically along for the ride.  The upper body needs to stay in a tilt position through the swing.  Do not let the upper body pull up.  The swing should feel like you are throwing the bat with the body.  The hands will stay close to the body if they stay relaxed.  Any tension in the arms or hands will cause the swing to get out of sync.  The hitter is generating all his power from the forward momentum of the stride and the rotation of his body.  With this the batter will maximize bat speed no matter the size of the batter.  The weight from the back foot will move onto the front with the rotation of the hips.  The back foot will release onto the toes or even in the air.  The back foot does not squash the bug.  Every pro batter I have studied releases onto the toes or the foot comes slightly off the ground.  The evidence is here in this picture of Albert Pujols.

Contact:  This is the point of no return.  Everything in the setup, load, stride and rotation leads you to this point.  Some of the positions you should have at this point is hands should be palm up palm down.  The hands should also be above the ball.  Every pro hitter I have studied has the bat on a downward angle with the hands above the ball.  These positions should happen automatic if the upper body stays tilted and the hands and arms relaxed.  The front leg will flex and straighten to stop the forward momentum of the weight and the bat will fly through the strike zone.  

Finish:  The finish can help with the path to the ball but can not be forced.  The hitter should finish with one hand allowing the bat to fully extend through the ball as far as it can go.  I also like to see the bottom hand finish below the shoulder.  This helps prevent a big upper cut swing.  It also helps with the extension through the ball for power.  There is a slight upward motion in every great hitters swing.  This upward lift matches the plane of the ball coming downhill.