Choose 2 opaque colors that look good together. Black polish for contour works and looks best, but any dark color goes. I used essie beach bum blu & borrowed and blue, black to the future by nicole
Push a toothpick against a hard surface to make the tip blunt. We will be using this when we need to paint with more detail.
Paint your nails with two coats of your base color to make it opaque.
Using your second color, make irregularly shaped blobs across your nail. You can use the brush itself, or dot it on with the toothpick.
Drip a small puddle of black nail polish onto a piece of paper. Dip the tip of your toothpick in it.
Using light, tapping/patting motions, paint the border of the blobs using the black polish with the toothpick. Leave some gaps in the contouring!
Don't worry if your contouring isn't perfect. If anything, you should try to make the contours irregular - thick & thin, with gaps, etc
This is what a finished nail should look like.
You can change up this basic look by switching base & blob colors. I alternated base colors on my nails.