I made the dress with some moisture wicking fabric I found at Joann's, which makes running around cons a much less sweaty endeavor! I also added separate cotton pieces for the front and hem of her skirt.
The arm wings took a while longer - I made them out of craft foam with flattened wire hangers at their core, painted with acrylics, and attached them all to some square cardboard pieces. The cardboard pieces were covered with felt to help it blend into the dress better, and the outside I covered in flower petals since whenever she uses her powers flowers bloom, and I thought it would be cool to have it look like they're sprouting from her back with flower petals. :) It held up 6 hours walking around Comikaze and bumping into people, so I feel pretty darn confident in how it's holding up!