First of all, I'd like to say I really like the overall work, it's very good!
Well, I can say I like the way you worked the shading/lighting, it's very consistent. I also like the blurred effect you applied in the farther buildings, giving the idea of fog. In my poin of view, your work don't have a strong cromatic contrast, but the colors you chose were very well combined.
The way you painted the sky is also very good, I can really tell that was a stormy day in the picture. Last, but not the least, you managed very well your medium.
I hope my critique motivates/helps you in the future and keep it up!