I hesitate to call this "The Twelve Manicures of Christmas," because not everyone celebrates Christmas and these manicures are good for everyone!
On the first day of manicures... holiday lights! This was really simple to do. I freehand painted a french tip, then used a black nail art polish to draw the "cord" in a wave-like pattern along the bottom of the french tip. If you don't have a nail art polish or a thin brush, you could use a toothpick dipped in black nail polish. Then I got supremely lazy and didn't even use a dotting tool to make the lights. I just used the brush from the bottles of polish. It would have been easier with a dotting tool or a toothpick, so I recommend that. Then just top coat it (carefully, so you don't smudge... I smudged a little) and you're set!