1) Squat shoes will help provide a more rigid and structural base
2) Your stance may be a little too narrow (tough to be 100% sure from this angle, but looks like you could go another inch wider. A rear oblique view will tell more.)
3) Your back could definitely use some more extension. Stand up real tall with a proud chest and squeeze your shoulder blades together and down (if you do this right your elbows will be down more and you'll be able to get your hands in closer together by at least a fingers-width each side.
4) Control your speed. You are divebombing to the bottom (especially on the first set) and it's a bit of a collision in the hole. Control the speed and think about building the tension down the your hamstrings and through your hips.