Reacting to where the pitch is takes a lot of practice and instant reaction skills.

What you need (set up):   Two balls, a [tag]batter[/tag] (with helmet) and the coach.   It is best to do this [tag]youth baseball practice drill[/tag] against the backstop or into a batting net.Youth Baseball Practice Drills

How this drill works:   This is one of the more advanced [tag]drills[/tag] for batting, but it is a great one to help a player learn quick reaction.   The player lines up facing the batting cage or the backstop, about 15 feet away.   The [tag]coach[/tag] will kneel down (at a safe distance), but close enough to toss the balls for the player.  

The coach will toss up two balls, one right after the other.   The coach will toss a high one, then a low one, and then shout which one he wants the hitter to hit.   The hitter must then hit the ball that is called.  

Results:   As you can plainly see, it takes a lot for the player to listen to your call, and then hit the one that you call out.   But, what it does is it forces them to develop their quick reaction skills to hit the ball wherever it is.   It could be high, or it could be low.