Wall Balls
Wall balls … it’s a love-hate relationship. Love the fact that they are quick and accessible; hate the fact that they are essentially med ball thrusters, and everybody hates thrusters. Regardless of your end of the spectrum, here are a few pointers to keep in mind as you develop your proficiency with this movement.
Stance — a good starting point is about a arm’s distance from the wall. This provides enough space to actually perform a squat with a large ball while also providing room to adjust to a bad throw. Stand too close and the ball hits your face (speaking from experience); stand too far away and you could wind up using too much energy to pull the ball back into your body if it falls short.
Squat — think of the it like just a regular front squat. Butt back, knees out, elbows up. Explode with the legs, driving from the heels, and keep your chest up. The ball should not be coming any lower than the collar bone, otherwise you are prone to hunch over and use unnecessary energy to curl the ball back up to the throwing position. 
If you find yourself hunching over as you come down into the squat, it could indicate a temporary lack of strength and/or mobility. If that is the case, use a lighter wall ball. It is better to practice the movement correctly, with full depth, rather than struggle through it with poor technique or incomplete reps (i.e. not hitting the line). I know it can be a blow to the ego, but make form a priority here. Become fully functional with 10 lbs. before your move to 12, 14, or 20 lbs. I can personally relate to this progression — I used 12/14 lbs for almost 6 months when I first started CrossFit before I felt strong enough to use 20 lbs in an actual workout. 
Final note: When you catch the ball for the squat, the hands should be on the bottom of the ball, which should be fully in your palms (not your fingers). I like to rest the side of the ball on my chin as I am coming down — I find it helps to keep the ball stable as I do the squat and close to my center of gravity. 
Toss — the toss is very similar to a basketball, minus the wrist flick. The momentum generated from your legs should propel most of the movement and require little effort from your shoulders to actually toss the ball. Your legs are stronger than your arms (or should be, at least), so use those muscles to generate most of your power. Think of arms as just guiding the ball to the right spot. (That is why I labeled this “toss” and not “throw”. Arms provide minimal contribution here). 
The toss is not just straight up but a bit forward, too. It may take some time to hone in the toss (I’m still working on it even now), so don’t fret it you don’t get it right away. Keep in mind that a bad toss can lead to a difficult squat if the ball lands far from your center of gravity, so cleaning up your toss could also help clean up your squat as you attempt larger sets.
Breath —  Take your deep breath at the top of the movement when the ball hits the line, and breathe out during the squat. Regulating your breath to the movement helps immensely when pumping out large sets. 
Reps — the ball should hit the wall at the line (for women) or above the line (for men) before it comes back down. If the ball doesn’t hit the line, go ahead and no-rep yourself (you knew it was coming, Sammy!). Wall balls are an easy way to keep yourself accountable to CFSH integrity, and at the end of the day you’re just giving yourself a little extra fitness. In the wise words of coach Tim, "it’s just wall balls!"
Hope that helps.
Until next time,
P.S. Don’t forget to clean your balls!