Your guidelines and rough sketches are great, but try adding a little volume and curves to the arms and legs. Try lightly erasing your lines and going over them again, making them smoother, and not as sketchy, so your drawings look better.
Your drawings are amazing, given the span of time you drew them in. But you should keep this in mind that you need to take your time in drawing the figures. Don't pressure yourself to complete the drawing within a minute or two, because it's impossible to achieve what you want if you set impossible goals. Instead of taking 1 or 2 minutes to draw the figures, first start by taking 10 minutes draw what you want, and then gradually decreasing the amount of time you have by 30 secconds every day. I hope this helps.
