I suggest more gesture drawing, more speed and scribbling, especially in the 30 second and 1 min warm up pieces. By focusing on just the outline your pieces can be rigid. Also try out blind drawing (where you only look at the reference and not your own piece).
One specific part is in your last piece you see that you fill in the shorts and top. Imo this kind of "left brain" practice (Dr. Edwards) can be bad because it means you thought "this shape represents the shorts, let me just fill it in". But if you forget symbols and objects, and go down to the level of just shades, lines, curves, I bet there are actually many curves and forms hidden in the shorts. Her buttocks, hips, etc.
My suggestion would be to spend more time in the 5-10min range atm. I think you are still a bit inexperienced, so won't benefit too much at this stage from the shorter timeframes like 30 secs. I think it is too short of a timeframe to make good anatomical observations as a beginner.
I believe it is much more valuable at this stage to gain a better understanding of the human body through keen observation in longer time sessions. Then consider revisiting the shorter sessions as a constant staple in your drawing routine further down the track, when you are more comfortable in your knowledge of the human body's shapes.