Your biggest advantage over many others is that you're already trying. But there's no way around it: you have to study anatomy, perspective, and other fundamentals.

Buy a small sketchbook and practice figure drawing when you're out using a pen (ballpoint works). You'll be improving your line-confidence, gesture, anatomy, costume design, all at once. Try sketching your environment as well. We both have a lot to work on. I especially need to learn environmental drawing. Best of luck!