Figure drawing day 6-7, 30m class, daily practice.

Looking back at my previous drawings, I realized how much improvement has happened in so little time. Thanks, in no small proportions, to all the guys critiquing my work here. Thanks.
Often I felt like stuck on a plateau, then a glimpse at my old posts, and it all goes away.

https://imgur.com/a/GmB4Cmh

Still, there is so much room for improvement, here are my critical areas and ways that I thought of strengthening them:
-Shoulder and leg length is often wrong. A good manual of proportions will fix this (Loomis figure drawing seems good).
-I have no idea how to draw hands and heads. A good book would help (Loomis head and hand seem what I have been looking for).
-Figures are often stiff (Drawn to life, even if thick, seem good).
-Drawing without references is hard (Imaginative realism seem the book I need).
-My routine might need a tweak (Not sure if Drawabox+30m of gesture, is what I need).

Thanks for having got at the bottom of this post, let me know if you know any other ways, or materials, that I can use to improve.