The most basic youth baseball fielding drill is playing catch. Coaches can never emphasize this "drill" enough, since for beginning players this is mostly a game of throw and chase. Other drills should focus on the catch-and-throw exchange; getting into proper position to field grounders, and fly balls; using both hands to field the ball; and general game situation fielding.
Relay Line Drills
Assemble four to six players in straight lines about 20 feet apart. The first player turns and throws to the second player, who turns and throws to the third player and so forth. On overthrows or missed catches, the next player backs up the play, fields the ball and makes the next throw in the sequence. As the players improve, increase the distance between players. This can also become a competition between two lines, seeing which line can relay the ball up and back the most quickly. This drill works on throwing, catching, getting into proper position to receive, the catch-and-throw exchange and backing up plays.
Backhand, Glove Hand
Little League players need to work on the most basic fielding drills again and again. A simple exercise that affords lots of repetitions is the backhand-glove hand drill. Players pair up 15 to 20 feet apart on the infield dirt with plenty of room between pairs. They throw easy grounders back and forth toward each other, alternately working the backhand side and the glove hand side. They can pick up the pace of their throws as they improve. This allows all the players to do plenty of glove work in a short period of time. This also teaches players to work in tandem to help each other.
Soft Hands Drill
This drills teaches players to crouch into proper fielding position -- bent knees, glove hand down, throwing hand above the glove -- and catch the ball with soft hands rather than stabbing at it. Spread three or four lines of fielders on the infield dirt. Have the player at the front of each line wear a flat training paddle or an oven mitt instead of a baseball glove on his fielding hand. Start out by throwing ground balls toward the fielders. To catch a bouncing ball with a paddle or oven mitt, you must pull it into your body to absorb its momentum, then secure it with your top hand alligator-style. Place ground balls slightly to the left or right of the more advanced fielders, forcing them to quickly slide to get in front of the ball and receive it with two soft hands. As the players improve, progress toward using sharply batted balls for this drill.
At the younger ages of baseball, it's a big deal whenever a fielder actually catches a fly ball. This skill must be developed through careful repetition, starting with tennis balls or softer training balls for safety reasons. Also start with hand-lofted fly balls to tailor the height and distance to the varying skill levels of each player. By using assistant coaches and parent volunteers to run drills, a youth league team can form several outfield lines to get lots of work done in a short period of time. As the players improve, force them left and right and up and back to get to the falling ball. Mix it up to keep things interesting. Add height and distance as the players progress, hitting the ball instead of tossing it.
While the bulk of a youth baseball practice should focus on fundamental skill work, each session should also feature game situation team defense. Put players into the defensive positions they will play in games and use any leftover players as baserunners, starting at home. A coach hits the ball, the baserunner (or baserunners) takes off and the fielders try to get outs. Fielders learn to react to the runners and go for the easiest out. Runners learn to react to the fielding play while trying to advance. Rotate the baserunners into fielding positions and the fielders into baserunning.