I don't know why I feel like you could improve on the composition on the drawings. I've seen like you give good context on some of them and I like it. Maybe I'm referring on your latest drawings in general. It's like okay I am on this step, what would be the next one? That would depend on the style you'll put on the drawings, because it would be nice to have consistency on the gallery you have I could say a little bit more colorful won't hurt a little, if you can find a way to give them a little bit of realism on the drawings, I know it's difficult and I find it hard too, like there are artists who use the colors in such way they can quickly immerse you into their worlds. I'm putting this example : twitter.com/gigideegee, I find this amazing and I hope you could go to that direction too, or at least give it a try.
From a hobbyist point of view I say you're doing great, you could find tools that could guide you into defining coloring and shine even more your drawings
I think you have a good handle on colors, you can try to switch things up by mix matching colors to give it a different look. But I believe you got that right. After looking over some of your work I think there is room for improvement on anatomy, you have the basic form and it looks good But, some perspectives of the body and poses can be bettered.
shading, cutting down on saturation. and using more colors to add to characters. like if the color was blue, using purple for shadows . while using light blue or green for the light. to create more of a harmony within the art. that would be the only thing that i would improve.