2nd June 2011: Neck feather thing So, writing about this retrospectively...
I pinned a strip of tulle around the neck of my sewing mannequin, and started arranging the feathers on it, gluing the feathers to the tulle (being careful not to glue them to the mannequin) until it looked like Yzma's neckwear.
Then I took the strip of tulle + feathers off the mannequin, put another strip of tulle on top so that the feathers are sandwiched inbetween, and sewed the layers together. I did add more glue too.
After that it was just a case of putting black fabric over that, and some fastening in the front.