I find that you can make things look alot more realistic by removing the elements that initially make it look real in the first place. I made this pic in carrara and rhino, then took all the color out in photoshop except for the browns and whites. Tell me what you think please.

The general effect is very sound, however there are several things which keep it from being really good. Contrast- the lighted section of carpet is very good. The bed is very poorly contrasted, and therefore flat-appearing. Lighting- a monochrome effect doesn't have to be dull. The bedpost is obviously mettalic, but has no phong,no reflection. Composition- the lightbeam is an excellent effect, but the sizing and placement of the bed make it a distraction. My advice? Lose the bed, and use something more compositionally appropriate- a tall chair with pillows and a draped shawl, perhaps. Work on the contrast, and light effects. Also, something outside the window would be nice- even if it's heavily fogged and blurred, as if looking through rain. Hope I could help!

Oh ps- I don't think you can edit posts here, can you? -one thing that REALLY helps in CG is imperfection. People spot perfection, and say "oh, it's a computer pic". Add some randomness to the quilt squares, as well as reducng the size along the y-axis. Give the wall panels some irregularity, and of course the window wall will have narrower panels at the corner, widening on approach. Also, why not throw a few dust motes in that sunbeam with a light fog?