I think all of us could cuss every time we wind up our extension cord and than go to use it later and it is all tied up in knots. Here is a simple way to coil it so it remains tangle free without a cord reel. A good cord reel is not inexpensive, and this trick uses no reel.
Stretch out your extension cord, than bring the male and female ends together.
Tie a loose single knot in the other end of the cord, leaving a loop in it.
Grasp the cord below the loop and feed it through the loop creating another loop continuing to work your way to the end of the extension cord. That's all there is to it. Now hang it on a hook and forget about it until the next time you need it.
To unwind, grasp the top loop in one hand, the male and female ends in the other end and stretch the cord out.