Here is a quick and dirty lighting setup for test renders...

Create a poly plane.

Set the environment lighting to a light shade of grey. Camera attributes>environment.

Set the render mode to mental ray. Select production fine raytrace.

check final gather.

render.

Adjust env color, render, repeat until you are happy.

This gives a pretty good and fast result with soft shadows.

note:

(1) the model is just some crappy ass thing I box modeled in 30 sec to show the affects of the render settings

(2) for the dark shadow on the side you could add a small point light or and area light in the scene or you could play with global illumination and a reflector board but these basic settings are usually good enough for fast clear renders.