Your drawings look proportional to me and have nice curving lines. Some of your drawings, though, are so small and softly sketched that they're hard to see. Some of the best advice I have been given has to do with speaking but I think it applies here.
When I think I might be wrong or I'm unsure, I speak softly. I suppose in the unconscious hope that my mistakes will go unnoticed? But we WANT to notice our mistakes in our practice. Our errors will still be errors whether we whisper or shout them. So my best advice would be to give yourself more space to draw. Get a drawing utensil that marks heavy and dark and draw your lines with commitment, even if they're wrong. you'll be able to see what needs improvement better that way.
Thanks for sharing your work!
-Rain
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