Here is my current methodology. I'm taking an object (in this case an unposed Dinosaur) setting it up in a preset lighting rig, and moving the lights around to see what happens. I'm currently playing with a "three-point theory" setup, but am open for other setup suggestions. I will be modifying multiple variables and aspects of my three-points as I can to see what happens.
Here is an animation to help visualize what I'm doing. The floating cones are proxies for the lights themselves (you can't directly see the lights in a final rendering). As they rotate you'll notice I've included the new angle on the right for reference.
After cranking out this first test version I realized that my lights aren't very well individualized. In future batches of these I'll be colour coding them and sizing them so they tell us more about what I've done.
For the time being red is my "Key Light", blue the "Fill Light", and yellow the "Backlight". For colouration the key light is a cooler colour (blue), fill is a warm, and backlight is a low grey. All these lights angled at 45 degrees to the ground from the sky, and are opposed to each other's alignment by 120 degrees. They all are "distant" lights, which is to say they apply light universally throughout the whole 3D scene (as opposed to a spot light or blub that function much like the real life lights that share those names).
Variables I'm planning on testing include strength and colour of ambient lighting, colouration of the three colour sets (which I've obviously started on), and angle from the sky.
Any suggestions on other test variable, light techniques, or things I've missed altogether?