dont worry if you cant get parts of the figure in 30 seconds at the moment, with the time slot forcing you to make fast decisions youll be quicker in due time, these exercises mainly help build your visual library and capture the overall pose which in fact you did very well. keep up the grind friend
Hi !
The main problem I can see in your sketches is the lack of proportions.
It seems to me that you're looking too much at you're drawing and not enough at the picture. Those kind of exercises engages the look, and you should look out of the picture reference only to position the start of a stroke and immediately get back to looking at the reference.
And when looking at the reference, you may compare the sizes of the body parts (head, shoulders, hands, pelvis, etc...) to adjust the proportions, and also pay attention to the voids around the body.
Also, I don't think in 30 seconds you can get the time to capture facial expression. Maybe try longer time lengths to do so.
Hope it helps you and good luck !
Look at the overall silhouette of the figure. Try to use long continuous lines instead of breaking them part by part. Forget about getting it anatomically correct and focus on the movement.