Fran might be right about the saddle tipping you back a bit. It certianly looks that way in this picture. Remind me and we'll try something different with the padding tomorrow. This picture is also a really good illustration of what I'm talking about when I say you need to put your shoulders back and bend your elbows. Your elbows are better here but you're still trying to hold her head down. It's better to keep a straight line from your elbow to the bit.
Both of you look more relaxed here. We might want to try putting your stirrups up a hole, though. Your heels are down, but this is pretty long.
Again, nice and relaxed.
I think this is the best picture of the group. Your shoulders are back and you look really nice. Allison's head is way up (of course) but she's stepping up nicely under herself.
Also nice. You look a bit stiffer here, but still fine.
This was the very first canter attempt. Weee!
See how your feet have come out in front of you? You're much less balanced here than at the trot.