Say, these quick sketches, 30 second, are totally striking, starwave. That's very spontaneous. (Even the 1 minute poses)
I've got one idea of improvement: I love how much freedom of lines in your half-a-minute sketches, but if you're new here on this site, they have a little bit of rigidity in the perception of edges. Why don't you please loosen up your hands, with Crayola crayons, on notebook paper, with 35 minutes of 30 second drawings?? (2100 seconds/30 secs=70 quick sketches of bodies, all with your whole shoulder, instead of your wrist)
The reason is because, it can and shall aid you in making visual communications, with the bold strokes, done very lightly first, and to spend less time of the details.
For more vital details, be sure to look at this drawing tutorial from Youtube.
https://youtu.be/Mm66LOQgz-o
This has some related info that's applicable to anything and everything.
My hat's off to you.