As you can see, I have created some boxes to block the light in certain places, allowing for more shadows to cast. By turning the viewport to Spotlight, you can manage to see which parts of your scene are exposed to light:
You can find the settings of the Spotlight used in the scene below:
The GI Environment has a light blue color. I was experimenting with different shades of colors, and I found this to be most suitable:
I used V-ray 1.5 as a rendering engine, and rendered with a VrayPhysicalCam:
It is all about testing with different values in f-number, shutter speed and ISO. Vignetting was turned on to make corners darker.
When you are testing, it is advisable to render at low settings and at low resolution for quicker renders, and when it is time to render the final scene you can pump your settings up. I'm using Linear workflow in V-ray, these are my settings:
My PC couldn't handle a 1200*1600 render, so I had to use region rendering and then stitch all the render pieces up in Photoshop. Glow and Sharp filters were added in post production. Here is the final render:
Hope you enjoy ;)