ok, pomp, not gonna lie, your drawings are good and all but...
This looks like DeviantArt grade cringe.IDK what it is about it, but something about looking at it makes a little bit of me make a lemon-eating face.
I agree with blocky. I'll critique these and give advice.
Generally I'm okay with most of your non-lewd art, (i mean its not the best either but that's not important)

OK first image.
Well, can't say much about proportion, as it's topdown, however, that right foot is smaller than the left.
Actually, I just noticed, the eyes are somewhat large in this image, and the mouth is... strange. Also, too much blush. She looks like a very leafy tomato.
The linework is, well, awful. The toes seemed rushed, and the hands are disproportional.
To improve your lines, make like a million sketches before you use pen, or, practice the pose until you are comfortable with drawing it all. Varying line thicknesses are important! Seperate background from the character by thickening them a pinch, as well as clothing, or other things that are apart from the object behind it, (for example the arm on the stomach).
P.S if the paint isn't waterproof, why isnt sweat effecting it?
Eh. Next.

Oof. Theres lots to talk about here.
Did she break her arms? As I said before, practicing the pose would have prevented this.
Her eye covers like 50% of her face, and the blush is back. Also, you screwed up the hair, the little split was in the first one, but it seemed to have rotated 90 degrees. Hmmm... am I onto something with this tomato theory?
The mouth... doesn't express much, neither does the eye. The neck is also small, was this intended to be a side view at first? Practice those poses! Her legs stretch into the depths of the earth. They are also really big. I see you put more detail into the hands, but the lines still arent fluidly outlining the object they need to be outlining. Making the lines a tad thicker would help.
Not as thick as her legs though. Speaking of which, are those knees? Proportion comes AFTER anatomy class.

I'll deal with it, as soon as you improve!
Her shoulders got dislocated, too. Tragic. I don't have much to say here, it's just ''muuh anatomy'' and ''muuh practice'' etc etc.
Don't give up! Improve but dont force yourself. Draw when your brain is most active (after morning coffee, in the evening, its subjective) and try to teach yourself!