I won’t comment on technical stuff i guess the wip people already help you out with that 
I’d change the color and intensity of the light to make it fit the mood better, i guess some cool tint might work better.
Maybe it would help to make the graffity on the wall more interesting, it might help improve the strenght of the image if the graffity fits her mood or if it does exactly the opposite.
For me it is just a crying person at the moment, since there are no hints why she cries and since we only see her head there’s no pose/action or so hinting what happened. But well maybe you don’t want to make it really clear. But i think it will need a lot of small mood/color/ refinements to make it real good without a hint of a story because that’s pretty hard to do.
The background could play a role here, see her silent silhouette by daniel conway, there’s no clear story there but the whole setting is pretty evocative.
The composition also isn’t very good at the moment it’s not bad but it doesn’t add anything. It hard to get that right, i know, but sometimes a good composition can help what you want to convey.
Lots of comments from me, sorry about that i know how hard it is to create good artwork ^0^