What hint does the author of how to jump start a car battery give for remembering that you should connect the positive clamp onto the battery before the negative clamp

She asks you if you can give her car a jump. ... Before you try jump starting a car, you need to determine that the battery is the reason the car isn't starting up. If you ... Unless you want to see flying sparks and a possible explosion, do not connect the negative cable to the negative terminal of the dead battery.