well first off, imo improve your habit of posting WIP, we won't know what you need to improve on if it's not all there.
if you want pre-critique, show a friend on skype, irc, etc.
second, if it's supposed to night, you'd want everything a darker tone right?
third
Gradients make everything better
heed these words, they speak truth, starting with the sky, when you look up at night, you don't actually see black or grey, you see very dark blue, because the light projecting from the stars gives it that color, however in flash the star glow won't really effect the sky as such, so try and mix and match your colors, look up some references.
