I always start training with a gentle jog around the bases in preparation for the training session. One session I do every week is the arm warm up for throwing and catching.

Arm Warm up for Throwing and Catching
One partner should be placed on the foul line and the other in the infield or outfield as instructed by the coach.

1. Gripping the ball correctly across the horse-shoe-shaped seam is a must when it comes to throwing the ball. To do so the thumb must be placed directly below the upper fingers, then step towards the target and snap right through the target area.

2. Throwing the ball:
From a L-shaped point the arm swings down, back and up, then the forearm and then the wrist pass the head above the shoulder level.
First the fingers remain on top of the ball throughout the motion.
The hand snaps straight down, as the throwing arm continues across the body and it should finish beyond the opposite knee, then the body follows the arm to complete the throw.

3. Catching the ball:
To catch the ball the body needs to move in front of the ball to catch it.
For balls above the waist the little fingers are placed together, the watch the ball entering the glove.   However, a top ball can be caught with a free hand.