I've tried rotating the environment to move light sources onto different parts of the object, but all the environments have the light high up on the "ceiling" of the environment. I really could do with a light source being at ground level or shining up from the floor. Is there a way of rotating the environment up and down as well as left and right?
In the environment tab there is a "height" slider, use that to lower the lights.
Let us know if that helps.