I took some advice from responses on my last post and started doing full class sessions with 30 second, 1 minute, 5 minute and 10 minute drawings. This definitely helped me a lot, and I'm noticing a lot of things I could improve on. Here's some pics of the most recent session (sorry if they end up sideways again, I've never used Imgur before). Any feedback or tips appreciated, especially related to shading which is something I want to put more work into.
It looks like you captured the momentum of the specific poses very well, especially in the third row of the first picture. (Take for example the figure spreading her arms and stepping forward, specifically the way the torso connects to the back leg.)
As for the shading, since I don't have much experience working digitally I may not be able to give you specific advice for that, but maybe it would still be helpful to establish a kind of "routine" for shading, like blocking in the overall shape of the shadow in a light value first, then darkening its core and after that working on the details, maybe even doing that in a specific order.
In the end, it is a matter of what works best for you.
I hope, this was helpful and wish you a great day!
A good tip for the shadows: You can very lightly draw the outlines that catch the light and accentuate the shadows with thicker outlines or with a bolder pencil. Having several pencils really helps (HB, 2B and 5B for example) to bring out the shadows :)