I also applied the reflection and the glossiness map. The IOR I control the strength of the reflections on the leather material. The dark metal I used for the windows and the steel is set like this.
The Carpet material is pretty easy and nothing special. Just some color corrected fabric texture in the diffuse slot and a black and white version of the texture in the bump slot to create some kind of a fabric texture.
Big round huge fat whatever lamp.
Once I saw a nice big ceiling lamp on a website and decided to use this in my loft scene, because it makes a nice soft light.
The texture for the lamp is a 2Sided Vray material with a VrayMat in the front side material slot. The color of the material is set to a light gray. That all!
Different light settings
To light up an interior scene you need some more lights than just one. So first I applied a ceiling surround light for the indirect lightning of the scene.
Second I put a big and bright light inside of my big round fat lamp with these settings.
The small lamps on the table at the wall and the small couch table I used a plane vary light as well. I made it a really small light with a high multiplier to create more sharp shadows.