After players master the throw to first, they need to learn how to throw out the lead runner. This [tag]baseball skills drill[/tag] will help them see the lead runner, and also be able to make a decision on throwing to first base, or to second.
What you need (set up): Set up a regular infield with all positions on the field. Have a runner on first base.
How the drills works: This one is pretty straightforward. With the runner of first base, you can hit to all of the positions and have them throw the ball to where the lead runner is headed (second base). Go through all of the positions and force them to not only field the ball, but to make the decision to throw it to second base rather than immediately to first.
Note: To make this [tag]baseball[/tag] drill even more interesting, you can either put a player on first and second, or just on second. The first option makes the player throw it to either first, second or third, depending on the lead runner, and if they can make the throw on time. The second option can be done with the player on second base making a decision to run or not to run, making the fielding player decide to play the runner on second, or make the throw to first.
Another great way to add a little extra to this [tag]drill[/tag] is to allow lead offs for the base runners.
Result: After continuing with this drill over several practices, your players will learn to make the play and react to the different running situations they are going to be faced with during a game. By having the repetition, the players will learn to instinctively make the right play over time.