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.

Lunging and Over Striding

Lunging forward during stride

Many young players fail to keep their weight and hands back when striding toward the pitcher. A simple way to work on this is to have players take (not swing at) pitches during batting practice and freeze until you have time to look at the position of their hands. Also, striding from their ready position (or stance) over and over will help remove the lunge from their swinging habit.

Over Striding

Over striding is a serious problem for many hitters, leading to movement of their head and loss of balance. Often, widening their stance can help correct this problem (they simply can't stride as far). In addition, placing their ball glove six inches in front of their lead foot during batting practice can help them from striding too far. Some hitters reduce their stride by trying to simply pick up their front foot and placing it back down (it will still go forward when they are hitting).