Alright, don't know how much this will help since drawing is mostly practice and trial and error, but if helps, then awesome.
For starters, I'm mainly a digital painter, so me doing this quickly leads to a messy image, rather than something clean and such. Plus my forte is not anime art and I don't consider myself very good, but I'll try to help nonetheless. When painting over it, I noticed you draw a lot of straight lines. When drawing, try to think more "curvy" and shapely when you draw. Especially when drawing females. Females are curves.
I didn't mess with the anatomy much, since there are a lot of things you could change around to make it more "realistic", and I think it would lose the point of the paintover if I changed around the entire image. I will point out however, that the pose throws me off, probably because you removed the pole she was leaning on. So having her stand as if there's nothing supporting her makes her look like she's floating. Her legs don't look like they balance her, and the arms without the pole are pretty awkward.
With the face, try to make the eyes more round. Both themselves as well as the pupil. You made them too oval, which gives her more of a cat-like look, rather than a human-like look. Think more along the lines of circles when it comes to eyes. The face itself also should have smooth lines.
Coloring and lighting: First, pick a light source. The area where the light(s) comes from will help with shading and coloring. Coloring and lighting go hand in hand, and one helps the other. So choosing a light source will help with color placement, as well as where to put white shines etc. Also, objects that are further back are often tinted blue, purple or grey. Objects that are closer are often tinted more orange, red or yellow. This can help with creating an illusion to take away the "flat" feeling from an image if you want to give it more depth.
Also, it's best to work at a larger canvas size while you draw, and just make it smaller when you post. Don't know if you are doing this, but it helps with the detailing process. It's hard to draw on a small canvas.
I didn't touch the background, since that's an entirely different subject. I'm trying to keep it simple since you're a beginner and such. But you are improving at a good rate, and the more you draw the faster you'll improve. Keep at it, I look forward to seeing your progress.