This is the point in almost every painting where I could just turn it to the wall and walk away. The initial buzz is over and I start to struggle. Something is not right with the buildings in this one but I can't figure out what. Terry Miura, who taught a painting workshop here a couple of years ago said, in effect, " Figure out what's wrong and then fix it, don't just muck around hoping it will get better." So I work on the hills and sky a bit more and leave the buildings until the answer comes.
Hope my learning process aids your understanding! Thanks for your comments and suggestions.