OK, so it took Joy snapping me in the side of the head with a big rubber band for like a week straight before I could remember to look both ways before crossing the street, but I did finally learn.
Also, I had a friend in high school, we'd sit under the bleachers during football practice, and he'd tell me about this guy called Ohm, and why not all laws are bad. It took me all season, and most of the playoffs, but I think I got it finally.
Now this guy Ohm, who sounds like the noise someone mediating makes-"Ohm, ohm, ohm, ohm"-well, he figured out three electronic things that are related.
The way I finally remembered it was my buddy Ralph telling me, "Virgins Are Rare." Now, what that means to me is: Volts = Amps x Resistance
That might not mean much to you now, but I use it a lot when wiring up a Jeep. With most things in the Jeep, we know they work at 12-14 volts, so if we can find out the resistance of something, we then know how many amps it will need and what size wire to put on it, and what size fuse it needs.
The other thing he taught me was "West Virginia." This one is good for lights:Wattage = Volts x Amps(W = V x A - W VA, get it?)
Take the rated wattage number printed on the bulb, use that 14 volts from before, and you can figure out what size fuse and wire you need for lights. I oversize the fuse to the next one up.
So with knowing "Virgins Are Rare in West Virginia," and some math solving for "x," that even I know, you can figure out most wiring and fuses needed for your add-on Jeep parts without getting hit in the head with a big rubber band.