Listen, we all gotta start somewhere! Opening yourself up for critiques like this is especially brave for a beginner artist, but it can only help you focus and improve faster, so you are doing a lot of things right.
I think your 30 second warm ups are too short and a little too small on the page. The point of the thrity seconds is to practice getting the WHOLE figure down in a short amount of time. One of the founding principles of contructing the figure of a human or anything else complicated, is to get the large general shape of the figure before you start adding smaller details
I think you are getting a little distracted with the torso and forgetting to draw your limbs long enough. This might be a result of working too small on the page and not allowing yourself to take to much space in your sketch book, which is a MISTAKE. Drawing the figures larger means more room for details and flexibility with proportions. Don't be afraid to buy a large cheap sketchbook that you can fill up with these quick disposable drawings. Paper is cheap! Your time is worth more than paper!
Using more space is especially important when you reach the ten minute long drawing. This figure will get more details and attention, so why not try to make it at least half the size of your page?
One last art tip is that you should never be afraid of a good old fashioned youtube tutorial for gesture and figure drawing. The one on this webiste is extremely basic and I don't think the techniques are pushing you forward very well, so it doesn't hurt to switch it up. You'd be suprised how often you can find a video for the exact problem you are having.
Keep up the good work! I see the anime head outline in your sketch book so I already know we have something in common!
1
1