If you are going for an evening feel I think a shade towards blue might help. Also, even in darker the environment will get lit from the sky. It will be more subtle unless there is a bright moon but regardless there will be light reflection from the sky. You can use this to create depth in your screen. I think you could also darken the edges of your scene as the light will not catch that which is further from the window. The light would be strongest on the hard surfaces of the window and this highlight here will also help you create depth. I hope this helps and gives you ideas on where to take this.

