Overall, my 2 cents are that you should redraw each picture a qouple of times before finishing it. Theres a lot of lines and shapes i know you could tighten up just by redoing them, and by that finding out for yourself whats faulty with them.
Also, i know your style isnt turned in that direction, but i think you need to have a better understanding of three dimensions. Your stuff is somehow overall flat, in a way that bothers me.
I know its boring as hell, but take a shoe (or something, not to simple though) and draw it from 3 different angles, then, without looking a the shoe (or whatever object you drew) redraw it from a fourth angle, by just using the three drawings you made as reference.
Or even better, if you have clay, sculpt from reference. Using two mirrors I made a clay self portrait in school once, and that helped me understand how a face s formed better than sketch i've ever made.
You have a great feeling for colors and style though, and i envy you for that.
Oh and another thing, try to avoid having stuff unfinished in the middle of a image. A floating head without a neck and shoulders is worse than one with badly drawn neck and shoulders.
Keep at it.