Looking back, I would say some things I wanted to improve in my seat included:
-Being less restrictive (I have worked on this a lot by routinely taking thigh and legs off in canter + riding one handed, and have improved even before the Von Dietz clinic, but keep checking in on it)
-Heels up tendency
-Working too hard to maintain canter! (too much driving)
Von Dietz made the point that when the canter seat is correct, the horse in canter becomes a sort of perpetual motion creature. The canter is easy to maintain in a steady rhythm without much effort. That was an "a-ha" for me because my current horse (unlike past horses, who would canter through any seat!) is *very picky* about me not gripping or restricting her at all. If I restrict her back, she will back off and really would like to just halt and declare "it cannot be done that way." If I let her flow, she is very forward and effortless to ride.
This is still a work in progress for sure, but two things have made a big difference for me:
1. At every landing of the horse's front inside leg, I open my hip angle even more. When I do this, my heels drop (magic!). And Em becomes a perpetual motion machine

2. I adjust how much weight is in my seat, depending on where we are in warm-up and work. Sometimes, I take quite a bit of weight off my sit bones and put it in my leg (calf) as I would when riding on terrain. This is nice for Em's back as she warms up.
I am much better doing these changes on one rein than the other, but it is getting closer. Perhaps one day I'll learn how to ride!
