Charlie,
There is so much to learn. I confess, I am a complete novice when it comes to lighting. I usually try to use shade or heavy overcast conditions when photographing people out-of-doors. Sometimes, I'll do the "north facing window with a reflector oposite" trick. I have hungrily read your descriptions of how to set up studio lighting in past posts (despite the fact that I have no studio and certainly have not a scrap of studio lighting). The trick with the string was a great idea - and apparently one that "every pro" knows but, it was a revelation to me all the same. Can you recommend a good book or other place to learn more about the art of lighting?