So the trick to good lighting is trial and error. Also remember that you can only really make the cast off lighting effectively, and the "light bulb" is better off in an editor. Also, while using an ordinary lamp is simpler, I primarily use rectangular area lights. For windows or lights on large flat spots with no nearby walls or angles, one area light that is slightly larger then the source (example: window) facing the model. This will create a natural glow around the edges of the source, but it won't create anything else. Next I take that same light, duplicate it, and using local rotation (as opposed to global), I rotate it 180 degrees, increase the energy, and then use the render preview to check it out, and adjust accordingly. The inward facing light that you first placed should be elevated off the mesh a bit, while the outward facing light should be quite close to the surface. You seldom need to use energy levels above 1.0. Also remember that the energy level will be spread out through the size of the lamp, meaning a small lamp with a power of 2 will light a small area rather brightly, but a large lamp of the same power will be much duller. Also, disable spec on the lamps... You cannot bake spec, and you will get a deceptive preview if you leave it on.
So that's my recipe. Area lamps offer great control, but will not work for everything, so preview often. PM me if you need additional help.
