looking for critiques and tips for figure drawings

These are all 2 minute sketches i did, is there anything i should focus on or any tips about how to progress? https://imgur.com/a/Rmx1WmL

Try applying a proportional chart for getting a better sense of the figure. According to the canonical one, the figure is 8 heads tall, with the crotch located at half the total height.
The 4th drawing you posted for example, is fewer than 7 heads tall.

Try drawing the line of action in, then the circles for the ripcage and then the circle for the waist. 

Seperate them, so that the legs come from the waist and not from the chest. 

After that you can add the connections of the bodyparts and add details :)

https://imgur.com/a/HZjol8N

I would appreciate any critique! These are the final few pieces of 30 minute classes. Thank you in advance <3