I definitely approve of your burning desire for improvement!
I can completely understand that feeling of "I need to get better at everything! ASAP! By thinking about where your weaknesses are and striving to be better, you're already on the right path.
Looking at your work, I'd say that while your colour work has room to grow, it's not that bad, so I'd say your main areas for improvement are perspective and learning to apply that to your figures so they have a bit more solidity. You have a decent understanding of how to place figures in a scene, your proportions aren't bad, particularly the faces, and your panels are readable. The main issue is your understanding of space, depth and volume.
Seek out the following books:
Perspective! For Comic Book Artists - David Chelsea
Colour and Light: A Guide for the Realist Painter - James Gurney
Making Comics - Scott McCloud
Drawn to Life volume 1 - Walt Stanchfield
For you specifically, I'd recommend Perspective! and Drawn to Life first to build up your figure drawing skills. A bit of observational drawing (like life drawing, doesn't have to be naked) would certainly help, and speed figure studies to build up your confidence in where you put your lines.