Youth players, particularly younger ones or those new to the game, often make the mistake of letting ground balls get too close to their body before making a stop, resulting in less reaction time if the ball takes an odd spin. It is important to emphasize the proper method of fielding - get the glove on the ground, use both hands, make sure to field the ball in front of you. This drill ensures that players must field the ball before it gets to them.
Divide your squad into two teams of roughly equal ability. Place two bats on the ground - one at the shortstop position, the other at second base. Next, line one team up behind each bat, leaving about six feet between the first player in line and the bat itself (you can adjust this distance to make it less for younger teams or more for older players).
Hit a grounder to one station, and have the player charge up and field the ball. He must not allow the ball to hit the bat, nor may he step over the bat to field the ball. In other words, he is forced to reach and field the ball out in front. When he has thrown the ball back (preferably to another coach), have him rotate to the back of the line. Alternate hits between your two teams, or have another coach hit balls at the same time to keep both sides working.
Let the players go through the drill once or twice, then announce a competition. Each time a player misses a ball, fields one improperly, or makes a bad throw, their team gets a point. Go through everyone four or five times, slowly increasing the velocity of your batted balls and making the players move laterally more. When finished, declare the team with the least accumulated points to be the winner (much like golf, a low score is better).
As an added bonus, give out sticks of sugarless gum to your winners. When you do your next drill, you might be surprised at the intensity!