Nice start on your SB so far! If i could give you one piece of advice would be to do more sketch and rough quick drawings instead of spending a lot of time on one particular one. of course you can finalize some sometime but i mean the more you draw the better (And the more different the better). try to get dirty a bit, with a paper sketchbook and whatever you favor, pen, pencil. It will improve your painting/anatomy skills really quickly.
Otherwise i really like the efforts you're putting into your different project. Keep the rhythm and you'll improve fast!