One of the keys to making an accurate throw in softball is having your body aligned with your target. A good time to work on this is while playing catch. Face directly toward your partner with your toes pointed at them. Bend your knees, rotate your core and line your shoulders up with your target. Without moving your feet, rotate your core back toward the center and complete the throw. This will help to create the proper direction with your upper body.
The next progression is to turn 90 degrees, pointing your hips and shoulders in the direction of your throwing partner. You will then rock back, putting your weight on your back leg and side. Next, shift your weight forward towards your partner and follow through with your arm and back side to make an accurate throw. By pre-positioning your body towards your target, you will get comfortable with the feel of moving in this direction.
The third component for creating proper direction is momentum. You want to stay athletic and linear with balance. You don’t want to be falling away in either direction while making the throw and following through. So, position your hips and shoulders to point at the target, rock back, and after making the throw, follow through with a few steps in the direction of the target. This will help to make sure you are staying in line with your target throughout the throwing process.
By using a good athletic posture with your body aligned toward your target, and maintaining momentum in that straight line, you are on your way to making consistently accurate throws.