Fine Homebuilding just had an article on this. While there are a number of ways to roll/coil cords, they recommend coiling the cord like you would a garden hose, in loops over your hand. This reduces fatigue, twisting and possible damage to the inner wires.
I wrap mine over my hand and elbow and then take the end, wrap it around the whole works and plug it in at the other end.....I have 5 and it works great....hmmmmmm here I thought everyone knew that....
my mom gave up trying to teach me to crochet....hehe
That's what I use to do with my long cords, I learned it from a "Rock Climber" they use that so the ropes don't get tangled when they are thrown from the top of the rocks.
Nothing like sliding down the rope only to be stopped by a tangle when your dangling in mid air! LOL