what you could do is adding the cast shadow of the furniture (fridge, etc.) appearing on the wall, on one side of it. This will give depth to the scene.
As an example: look at the cast shadow on the right-hand-side of the fridge here. It takes 2 seconds to add.

Also overall I'd recommend reducing the dithering everywhere (for example on the desk).
All you have to do is zooming on stuff (for comfort) and then hand-drawing a bit, to create larger areas of one single color (manually remove the noise). That doesn't take any skill at all either and you immediately get cool resulsts.
As an example: look at the cast shadow on the right-hand-side of the fridge here. It takes 2 seconds to add.

Also overall I'd recommend reducing the dithering everywhere (for example on the desk).
All you have to do is zooming on stuff (for comfort) and then hand-drawing a bit, to create larger areas of one single color (manually remove the noise). That doesn't take any skill at all either and you immediately get cool resulsts.