Be sure to think of what you want the viewer to see first. Some of these shots are sort of muddled - there's TOO MUCH to look at - like the glass or graffiti.
Be sure to use light and framing to draw to (or away from) some point in one way or another. Think about negative space and how that affects the interest in the photo. For instance, #5 makes the best use of neg. space IMO. Framing away from something slightly can help draw you to it.
Hope that helps! Let me know if I need to clarify. Keep practicing - looking forward to seeing what you get up to!
//Sparro