your perspective is really forced, meaning that your right vanishing poing is very near your building (which isnt how it would exist in real life). it's making your facade diminish very quickly to the right.
in terms of a quick sketch...
you can always push your darks more. dont be affraid to get bold and deep with your value // cast shadows are always a biggie because people tend to forget them // establish a specific light source
with that last one, decide a color scheme for your light. a professor once told me that even a white wall isn't white. which is true. no surface has one color/value all the way across it. try to cast rich, colorful light on to your objects, as well as rich, colorful shadows.
hope it helps.
ambition makes you look pretty ugly