First off, you need to be some kind of freak. This freak is someone who is flawed in the fact that they have no concept of time when it comes to working on stuff. Nothing can phase them. Not hunger, sleep, or even that massive cramp in their leg from sitting on the floor for five hours straight working on headlights, can distract them from creating stuff.
As far as knowledge, I think Drumnut hit it on the head. It starts out when you are four or five years old, and you just figured out how to use a screwdriver and some pliers. The Dremel, heatgun, etc. come later.
You also need to be fearless when modifying. I was sure I was going to totally ruin my headlights when I started taking them apart. This didn't make me more reckless, I just was concentrating on modifying them, not worrying about breaking them. It just turned out I got it right the first time.
I would recommend going to a junk yard and picking up some parts of a Contour similar to yours. Think of it as a craft or hobby. I do.
