Well the first thing I notice is the excessive amount of chicken scratching. I suggest getting that under control first of all, because it will be more difficult to do anything else with that.
Pic related, draw long smooth curves and follow the surface, don't scribble all over the place until it looks something like you thought. Put thought behind your stokes.
You're kinda doing the same thing with shading, scribbling in random directions trying to fill in the color. With cross-hatching you should keep the angles of your strokes consistent (pic 2 shitty example)