One thing that finally clicked was the fact that I need to support the horse with the outside rein. In lessons before I would not keep enough support. So, Helena found it all too easy to run through it and go off about her business, ignoring my cues (I still had issues with her wanting to go her own way in this lesson, but hopefully it's getting better). In the past I was always scared to use too much contact, but I think I'm on the verge of finding that happy spot where I am able to keep contact while still being flexible/elastic and going with the horse's movement.
And with support on that outside rein, I was also able to get her collected and keep her there for longer. Outside support, wiggle inside, nudge with both legs, and that seems to get her collected at the trot.
I was on the lunge for the canter, and that is seeming to get easier each and every lesson. It seemed as though I only had to apply my aids precisely but gently to get her going in the canter. Perhaps I've been thinking too much and trying too hard! My transitions down are improving as well. I seem to be able to get her down from the canter into a comfortable trot instead of a fast, slightly rough trot faster. I concentrated on not allowing my body to rock so much with the horse's movements but trying to sit deeper and letting my lower body go with the movement instead of my entire body.
I still need to improve on my overall position quite a bit. My hands tend to go into piano hands- I need to keep my thumbs up and pointed to opposite ears. My hands also tend to go too low and too close- they need to come up a little and in line with the horse's shoulders. We did some wide arm excercises in which I spread my arms WAY out. That actually helps quite a bit, because then it feels weird if my hands get too close together!
All in all, good lesson.
Maintain: Outside support on rein, collection, transitions up into canter.Improve: Transitions down into trot, position of hands.