See the full video tutorial here. And the speedtorial here!
Black and Silver Wavy Tips
After cleaning filing and shaping the nail and applying a base coat:
use the brush from the bottle of silver polish to paint the top half of the nail making the edge of the silver look like 2 waves/mountains/humps
use a very small striping brush and some black polish to make really uneven, lumpy lines outlining the edge of silver area and also filling it in with stripes. Continue to mimic the shape of the original waves with each stripe as you go toward the tip of the nail.
apply two thin coats of quick dry top coat (I always apply two coats of top coat when I have done a negative space look because it helps the nail feel smoother and more cohesive when you physically touch it)