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.

Proper Hitting Goals

The goals of getting a hit (short term) or to hit .300 (long term) sound reasonable at first. But having goals that are not within one’s control can lead to frustration, desperation and a lowered probability of success. A line drive caught by the center fielder should be considered more of a success than a bloop single over the short stop.

A more reasonable and useful goal is to have a successful at bat. Successful at bats are under the hitter’s control. They don’t depend on how good the pitcher is or a great defensive play. They don’t necessarily exclude a strike out. They can be monitored by parents or coaches and provide the basis for real improvement (which isn’t necessarily the case with batting averages). Such a goal also puts success within every player’s reach.

A good at bat first and foremost involves taking a good swing. Players should be taught to take a good swing or not to swing at all. A bad swing single is not a success at the plate. The "just make contact" mentality has hurt a lot of young players. "Good swing" in this context includes proper tracking of the ball to the plate, good weight shift, balance, etc.

The second aspect of a good at bat is swinging at the right pitches. This part of a good at bat will vary by hitter and experience. Generally, this involves swinging only at strikes or, with two strikes, swinging at pitches that are close to being a strike. For more advanced players, this might involve swinging at specific pitches in selected parts of the strike zone early in the count.

The third aspect of a good at bat is making adjustments, especially in relation to timing. Swinging late at the first pitch is fine as long as the swing isn’t as late on the next pitch, etc.

A good at bat is a short-term goal. Long term goals will vary by level and experience (and concentration levels for very young players). Batting .800, or having successful at bats 80% of the time, is a reasonable goal for many young players. When a player truly adopts good at bats as their goal, their batting average will almost always increase and they will get more enjoyment and satisfaction from the game.