Before trying anything mechanical, focus on the mental first! We tell our players in slumps to try and hit a hard ground ball to the SS or 2B. Now, I am dealing with 17-18 yr. old, not 13. We tell them to wait for a fastball on the inner half, and to hit that ground ball. If they are successful, one of two things can happen. One, the ball goes to the fielder and they are convinced they are seeing the ball and can be successful with a little more focus. Or two, the ball will go to the left or right of the fielder and now the player has a base hit. Start with the simple...