Hi amalskaer,
are you using any bump maps? it seems not... they may help make your render look more realistic.
also, a bit of dirt on the lower part of walls and that stairway would greatly improve realism.
furthermore, walls aren't generally stuccoed all the way to the ground... check out some options for plinths
on the stairs, the black part looks like paint...is that the intention?
the front and top of the tiles don't match. this kind of thing will cancel out any level of realism a render may have.