Other then it is hanging of a nail, it's not that obvious just how small this house is. And hanging of a nail just doesn't look that good. Maybe if you had a painting or something like that next(or near) to the house
This looks exactly like some wall art I've seen...little dioramas of sidewalk cafes. I think those who are into this sort of thing will recognize it for what it is. Maybe add a ladybug crawling on the awning to emphasize the scale.
What about the wine glasses (two). And the inside curtains for the bottom windows. Some sort of metal grill for the top two windows. what about paving stones for the of the house. To show that the house is nail to a wall, show some cracks on the plaster where the nail is and some other places as well
To show people that the house is nailed to wall. show cracks in wall or in the plaster which covers the wall. also cracks in other places to show that there is a wall there
-SHADOWS
-SOME COLORS
-SOME PARTICULARS
i will update with version 2 soon!