I chose to use a watercolor technique. You can find a tutorial for this effect on Beauty Geeks and on Rebecca Likes Nails. It's a pretty simple technique where you place dots of color over a base color, and then dab a large makeup brush dipped in acetone over the dots to create a watercolor effect.
For this look, I used a base of OPI My Boyfriend Scales Walls. The red watercolor color is Sally Hansen Insta Dri Rapid Red. To add a bit of flair, I put two accent rhinestones on both my ring finger and my thumb.
I've done watercolor nails before but I think this manicure turned out the best out of all of them. They key for me is not being afraid to use a good amount of acetone. I think I was a little skimpy on the acetone in the past so it didn't make the rings as effectively.
Day one: complete! Only 30 more to go... ;)
Here's a refresher on the prompts. You can grab your own version in my 31DC2012 intro post.