i think its really good.
if your going to animate it (even just a camera panning) i think ur about done.
if its a still pic i think u need a bit more.
you could explain the room itself by adding some sort of fixtures. like a bathroom, doctors office, etc. and you could have the shadow of the person who wrote the message on the floor beside it. but thats only if u want the viewer to know its recent rather than its been left there for ages.
anyway i really like the concept and it looks really good. now u just have to teach me how to texture and ur done