Starting off with two coats of Barielle - U Concrete-Me, I waited until the polish was sufficiently dry and then sponged on an opaque black polish. I am using a classic nail blogger favourite, China Glaze - Liquid Leather.
I smoothed out the gradient with Ceramic Glaze - Diamond Dust* and added two matte black studs from Born Pretty while the polish was still quite wet. I have found that they stay on far longer than by "gluing" them on with top coat. Seal everything in with your favourite top coat (I am still really loving the scented ones from Rainbow Honey!) and you are done!