If you use Gamma Correction, you won't need quite as much light in the scene as before. So, if you simply switch GC on, your images will look washed out. 

vilters is right about the light setting when your render an outdoor image, inside I would replace the infinite light with a point light with inverse square attenuation and ray traced shadows. 

Why don't you post an image you don't like here? I think we may be able to suggest a way to make it look better.

A ship in port is safe; but that is not what ships are built for.
Sail out to sea and do new things.
-"Amazing Grace" Hopper

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