You may want to consider looking for photography tutes. They tend to tell you how to light an object. That will help you with positioning. As for the rest of the light lab, that's a whole book right there. It's very subjective. How do you want your lights to be? I can offer a few tips though. If you are using spotlights, you can set them to track the object that you are lighting. (Buy clicking the "tracking" icon and dragging it to the object you want to light up) That will keep the light pointed at the object even if you move the object or the light. Also, I don't know if you can set the ambient shadow color in B4 (I don't think you can) but a good tip is that light casts shadows that are the complimentary color of the light. For example, yellow light casts purple shadows, and red light casts green shadows. If you don't believe me, break out a colored light bulb and see for yourself! Good Luck!