You should try perspective -- it makes a huge difference. I'm saying this because your already an established artist and acquiring new skills is the only way forward.
As for constructive criticism for this pic -- the buildings seem too 'smooth' and blended. Perhaps a little noise or texture will improve the scene. I understand that you did this from just one layer and that was a VERY brave thing to do. Otherwise, I applaud your intention to just go in and draw and finish.. I wish I had those intuitions!