How do I make the light shine evenly throughout the scene?

I have a directional light and illuminates some parts clearer and others darker. How do I get all the spaces the uniformly illuminated?

To be a little more precise:
Edit → Render Settings → Ambient Light

Click the Ambient Light box and then change the Color (using the Color Picker) to Light Grey.

  • white will illuminate everything evenly in your scene (will override all other lights).
  • if you add another light source turn it back down to dark gray.

If you want uniform lighting throughout your entire scene, you can alter the Ambient Light propertly of the Edit → Render Settings.

http://unity3d.com/support/documentation/Components/class-RenderSettings.html