I can't call myself a honorable person, in fact I can safely call myself the least honorable person in the entire history of humanity. A young developer living in the middle of nowhere. Shares left political view, likes to talk about philosophy, even if other people don't want him to talk about philosophy.
I was bored at art class.
Proportions, proportions, proportions.
Proportions.
It's really hard to understand the following, but you should try to focus more on what you actually see, instead of drawing what you know.
That step is totally necessary to let your drawings and paintings look like they're actual professional studies.
Hard to give you advice on that, because it comes with practice.
Anyway, as a proportion practice this is a good start. But, I think that charcoal is the best medium to do proportion drawings, because it doesn't really allow that much details, unless you're working with an eraser and highlights.
This is gesture work more than proportions. I suggest that you sketch actual models in order to understand proportions better.