That first photo is really pretty with the mist in the background...oooooohhh aaaaahhhhh
Okay, anyways! Your eyes are always up and looking where you're going...good! In the first photo, you have a nice, straight line from elbow to wrist to bit.
The negative part I am seeing is probably due to the BOOTS! Are they rubber? The tops are just cut straight across (not "spanish" tops) so your leg doesn't look as long as it could. It looks like you're having a hard time getting your heel down because of the boots. And in the first photo, I see what you're saying about your toe slipping forward. That forward toe slip has kind of thrown off your whole center of balance. Remember, there should be a straight line from your shoulder to hip to heel. You can see your heel is way too far forward. Get some new boots (and break them in!) and you'll be looking lovely!!
Overall, you two look very nice and clean too! Oh yeah, I know it's a schooling show, but next time don't wear a top with a hood...it will either hide good posture or make you look like a hunchback! Also, if your horse has a momentous canter, it will bounce in the air and just distract from your pretty presence.