Picture One: More depth in your heel.
Two: It looks like you came out of the saddle and onto the horse's neck.
Three: Again, you're too far forward.
Four: Leg slid back. Kind of hard to tell from this angle but it seems like you may have been too far forward. You're also leaning to one side and your shoulders have a slant to them. Where you looking where you wanted to go (not at the jump or at the ground)?
Five: I'd like to see your right arm come back to where your left arm is. A little more release also would've been nice.
Six: A bit too far forward.
I can't really see what's happening in the other pictures well enough to critique.