Proper Lighting Techniques

I'm looking for some tips and tutorials on proper lighting for unity scenes. I'm specifically looking for the best lighting for a virtual reality experience I'm creating. While baked lighting has helped, I still find a bit of lag due to the sheer number of lighting sources needed to illuminate the scene.

While I can't go to a ton of detail as to what the experience is for, I can explain what it is. It's is a large, 1 floor, Office, complete with a receptionist area, elevator lobby, and cubicle farm. Included are also board rooms and conference rooms. Because of the layout, lots of lighting is needed to make it look as natural as possible.