Here are a couple of practice ideas that are working for the U12 team. The drill we use is Around the Horn.   This drill teaches them not to panic when they throw and also call out the position to where the ball is going.

Around The Horn
Players start at their positions 2 thru 6.
The focus is on making a good solid throw and communicating where the ball is to go. .
The ball starts at catcher and progresses C-3B-2B-SS-1B-C
The 3B calls “third!” followed by 2B calling “second!” and so on through the progression.

The hope of this drill is that all throws are made clean without being dropped, dug out or moving too far from left to right.

They are also learning to call for the ball when the throws are being made. Variation can include the pitcher being the final receiver.

The skills worked on: Throwing, communicating.