Your loose sketches are very nice !
The colored pics feel unfinished: everything is equally important in them. If you would put some parts in shadow (less details) and make other parts more detailed (not so fuzzy), I think that would help a great deal. Chow 63 and 78 look great, you must have worked hard on them ! But I think the coloring can still be pushed a little further. Sorry, I can't explain it better, it's not exactly my area of expertise.
Keep it up, you have a good thing going on !