If you wanted to try a nighttime scene this works, except the barn is the same brightness and it throws off the whole scene a little bit. Just a note, just because some of the example scenes are monochromatic, doesn't mean you have to monochromatic as well, the color palette can be limited in other ways.Something I also forgot to mention the first time around, is that I think your scene is too big, creating a lot of empty space that isn't very interesting. Shrinking the space and rearranging some of the pieces could help make it more interesting. The question that should be ask is what is the focus of the scene? Once you figure out that, you can arrange things in such a way that your attention is directed towards the main focal point.
I have no experience when it comes to such scenes, but I think a website such as Adobe Kuler or Paletton might help you when it comes to generate and play with different color schemes.