What i don't understand is why you are making an image based on another render(and please don't say it's reall, it's to clean).
Don't you have an original image of the room?
If not i wouldn't even bother starting it, because you will make an interpretation of another interpretation and that will never look right.

And i agree with the others you have to read up on lighting, camera's and rendersettings a bit.

Also start with smaller objects not an entire room, try a pair of scissors ,a cola can etc.

good luck