Good start on the Gesture drawing, my advice would be to give yourself more time and to focus on line confidence. Scribbly sketchy lines are valid in shorter gesture drawings (This happens in my gestures occasionally) but I find it is better to have clear, confident lines to show gesture.
Sketchbook drawings are exactly what I'm talking about, though there is still some scribbling but depending on your goals at the time it is ok. I should also ask whether you are using whole arm to draw or just your wrist. It is ok to use your wrist for smaller details but don't forget to use your elbow and even your shoulder, it will help you achieve smoother, more confident lines.
All in all your gesture drawings are quite good.
