TIPS:

Bat Angle
Correcting a Weak Swing
Finishing the Swing
Flat-Snap Hitting
Front Toe Closed
Hitting Off Front Leg
Level Swing
Looping
Lunging and Over Striding
On-Deck Preparation
One Swing
Perfecting the Stride
Plate Coverage
Poor Timing
Proper Hitting Goals
Seeing the Ball
Stance vs Swing
Staying Closed
Stepping Out on Pitch
The Two-Strike Swing

Most of these tips come from the book Illustrated Hitting Guide with permission from the author.

Hitting Off Your Front Leg

The rear foot is pivoted up on the toe. Many good hitters actually have their rear toe off the ground an inch or so at contact. In addition, the advice of "squishing the bug" with your rear toe seems to emphasize one's weight staying back during the swing rather than going forward and pivoting hard with the back foot. This isn't a good image for hitting. The focus instead should be on getting the weight up on a stiff front leg.

Some wrong advice given to young hitters is to hit off your back leg. During the swing, the weight should shift from the backside of the hitter to the front side. Energy is transferred to the hands by the stiffening of the front leg (similar to pole vaulting). The back leg adds nothing at the point of contact with the ball; it simply aided in the weight transfer.