Nice work everyone. And thankyou for the votes!
could you share some of the lighting effects you did? like the light on the walls and the look of the window.
The blur is just right, nice touch!
Sure, I can give a quick explanation.
I use 4 lights to light my scene. 2 omni, 1 spot and 1 area.
I rendered the image.
Then I render an AO pass.
I rendered the chair and used it to make a cheap depth of field mask.
I also made a mask for the window for the dust and the lightrays.
Then I composed all the layers and added some more blurring and other effects.
Not much of an explanation, but if I had more time I would go into more detail. I hope that helped a little.