Nancy is very aware of body position and focuses almost 100% on your body, what it is doing in the saddle, and how that effects the horse. I ride with my heels way down and my leg firm and stiff, a product of lots of time in jumping saddles on explosive horses. An excellent way of staying on, a very bad way of staying soft.
Nancy wanted me to keep my leg loose and almost hanging, lightly on, with my heels almost level in the stirrup to my toes. She wants a stable upright core with arms that look like "L's." I really noticed this when Annie wanted more rein and would rudely shove her nose forward to jerk the reins and my entire body forward. By responding to this with a more stable core and leg I was able to prevent it from happening.
I also needed to give more support in my downward transitions which we usually blast out of. Letting Annie know where she needed to keep her head and neck by letting her know that I wouldn't be pulled forward AND would be a soft and supportive fixture for her.
At the canter I lean forward with my body (thank you jumping saddle) so when I sit up I take my legs off. I had to work hard to sit the canter while keeping my core still, my shoulders back, my leg on, and following with my seat.
When Annie got weak in the right lead canter and started picking up her left lead I learned that I don't help because my stiffer left leg and hip allows her to pick up the wrong lead much easier.
I also spent a lot of time learning how to generate more bend in her hind legs without making her go faster. It lead to a slower trot that was a better trot.
We really focused on my seat at the posting trot, and how you should SIT on the saddle. By sitting softer and staying in the saddle longer you can control the speed of the trot without using the reins. Nancy wanted me to sit almost slouchy, scooping my butt under me further and almost up then down softly. When I got this very distinct motion Annie went wonderfully. It took a lot of concentration to achieve that level of control with my lower back and butt.
This lesson was filled with highs and lows, spending so much time working on the nuances of body control lead to plenty of moments when Annie didn't look as "nice" but when I got all the body parts in line she looked wonderful.