This scene is set up perfectly. What you are missing to achieve photo realism are textures. You need to use textures to make photo realistic stuff, its a law of nature 
. You could get away with the tiles (though adding some dirt o scratches is also a good idea), the sink, mirror, all the metals, but you have to have textures on the door and walls. And also it would look better to have something behind the window. Could be just a flta plane with image.