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I'd say everything needs improvement, and I'm not sure where you should start... I don't mean to discourage you by saying that, so don't let my comments get you down.
The first major problem is the background. As I'm sure you can tell, lots of the lines are not straight. If you look at the gap between the house and building near the bottom, then follow it up... you see that the gap disappears. This is because you made the building hang over to the left more, thus covering the gap. If the building was like that, it would mean that it was tilted. The windows and general shape of it make the building look very distorted.
My advice: Look up "perspective art". It's not too hard to do and it will make your buildings look much, much better. There should be plenty of tutorials on the internet, so it should be easy to find instructions. Always use a ruler for things that are supposed to be straight.

The road kinda looks like we're seeing it from a top view. That would either mean:
a) It's on a hill and that's how it looks from here. However, the upper part of the road would be slanted quite a lot if it was on a hill, so driving would be awkward/dangerous. If you were building a road on a hill like that, you'd try to build it on a flat surface, not on a diagonal surface.
b) The road is not in perspective.
Also, look at the size of the sidewalk compared to the road. Half of the road should be wide enough for at least one car to fit on it, right? Most roads are wider to allow parking space, and roads in busier areas tend to have four driving lanes or more, not just two.

Try to be more consistent overall.

Now for the character... I know this isn't a very useful tip, but you need to improve the general anatomy. Her angle and pose also don't make sense. Look at her collar bone... that should be like, centered in line with her neck, but it isn't. Here are two other quick tips for now:
1) The eyes are located at the vertical center of the head. I've explained some stuff regarding that at the following link if you want a better explanation: http://cloudflash.net/arttips.php
2) The hair is very boring. One of the most important parts of an anime/manga character is their hair; it makes the characters distinguishable and unique. You need to make it more detailed and exciting.


Anyhow, keep at it and you'll get better over time. There's an insane amount of stuff to learn to be able to do good art, and some people just plain don't have good enough control with their hands to be able to draw even if they do learn all that stuff... It's not an easy path, but remember that drawing is supposed to be fun; don't ever let it frustrate you or whatever. Always look for ways to improve your art by looking at other work or by observing real life and try to apply it to your own art.