I started with three coats of Zoya Aurora (Ornate Collection), a medium purple scattered holo. I could have stopped at two coats, but I often use one coat more than necessary, just to make sure it doesn't look patchy.
As soon as Aurora was completely dry, I taped my nails diagonally with regular scotch tape and added one coat of Zoya Storm (Ornate Collection), in a way the same polish as Aurora, but black. I removed the tape quickly and finished with one coat of Esence Better Than Gel Nails Top Sealer. And yes, I did change the diagonal on my ring finger on purpose, as an accent nail.