Wall ball. Lots of repetitions. Find the form that works with your strong hand (hand placement, hand motion, stick head movement, release point, etc) and try to repeat it consistently with your off hand.
Especially focus on getting your hands up and away from your body, getting your chin above your front shoulder while your hands are extended, and being sure your "top hand" (your right hand, if you're shooting righty) always stays vertically higher than the hand you've placed near the butt-end. Be sure that, in addition to ripping through at your target, you are stepping, driving with your hips, and rotating your torso to maximize speed, accuracy, and a consistent release.