For the top, I bought a corset. I made the skirt with scraps of fabric leftover from Diva's costume, and a black tutu I found, and the tail was done using leftover feathers and a fan, in the same way that I made Diva's.
From the front.
From the back.
For the peacock feather tail:
I bought a fan from the dollar store (you know those feather fans you use for a flapper costume) and hot glue gunned the peacock feathers onto it layer by layer. It was super easy, and kept the feathers perfectly fanned out. Then I just laced the fan into my corset and used a safety pin on each side (hidden of course) to keep it upright. A store bought peacock headband finished the look.