Save storage space and avoid tangles by storing lights in "Light Balls"

Start by holding the FEMALE end of the strin in the palm of your hand like this:

Now wrap the string around your hand three or four times

Slide the lights off of your hand and start wrapping the lights around them

as you wrap, occasionally turn the "ball" around so it stay in a roughly round shape.
Once finished, you will have a "ball" with the male plug hanging off of the end.

To start decorating, just plug up the male where it goes, and start unwrapping the ball.
This makes it especially easy to wrap tree limbs, or just unroll it out down the edge of a wall.
These also keep easily in plastic tubs, and won't be tangled up next year!