I have a lot to say about your artwork and I'll try to sum it right here as briefly as I can!
You seem to have a good understanding of proportions, but it looks like you draw what you think is right opposing to drawing things as they really are, what I mean by this is that you don't seem to know much about anatomy but you have great potential!
Stop doing polished drawings, get a pencil, a sketchbook and start practising lines, ovals and basic shapes, draw from your elbow and try not to make fuzzy lines. Also, when colouring, don't leave those small blank spaces between strokes, it looks very rushed! be careful and cover all of the surface!
I really suggest you to watch Stan Prokopenko, Sycra and Draw with Jazza on youtube, you could really benefit from their videos, keep practicing!!