a) your legs/feet sort of drift back and forth with no definition. make each movement decisive and sharp, and use dimestops to show where the movements begin and end to make it look crisp.
b) change levels. bend at the waist, bend at the knees, etc. just be sure to keep your back straight, and be conscious of your torso in relation to your hips
d) clean up your flow. sometimes it looks unbalanced, other times it looks too constricted. try some bigger hand distances, and try to make sure both hands are covering the same amount of distance
c) muscle tension. play around with it, not just your hands/arms (helps with d) but legs (which will help with a) and back/abs (which will help w/b).