After perspective, shading is key. Presently there is almost none, yet it will be essential to define volumes, in ways that perspective can't. You have to decide on a light source and apply it everywhere. It could be strictly top-down, or 45° from a side (these are easy, but of course it could be anything).
Think of all surfaces (for instance, windows and door recesses), determine if perspective allow them to be seen and if they would be in light or shadow. Give shadows enough contrast that they are obvious.
At the moment, there is a slightly darker yellowish that is undecided: looks like shadow below the roof (but way too short), makes no shading sense around windows and door.