This was my first very involved cosplay - Dolorosa from Homestuck. I re-used the petticoat from my prom dress, just removing the hoops, rehemming it, and installing pocket holes.
I made a makeshift dressform from stuffed plastic bags, duck tape, and a little-used set of drawers.
The top tier and waistband of the underskirt I made of an old set of dress pants. I designed the lower tier skirt pattern based on medieval 4-panel skirts, except made it 2-tiered, added the asymetrical layer, and added pockets.
Instead of body paint, I wore thin grey cloves and attached painted acrylic nails.