2nd June 2011: Hat The hat was made using 0.5m of Fosshape (http://www.coscraft.co.uk/craft-materials/39-fosshape-600.html). I cut and sewed pieces of it together until it was about the right size for my head, allowing a bit more room for shrinkage because fosshape shrinks as it hardens.
To harden the black area I wrapped a salad bowl in towels and then put the hat on it and used a hot iron. I only partially hardened it because it wouldn't be very nice to wear if it was rock solid. Also that meant I could sew some wig clips into it and secure it to my hair (which was hidden under a mesh wig cap).
For the purple area I used a heatgun, though a hairdryer should've worked too.
The hat was painted using acrylic paint. I found that mixing a bit of latex in the paint made it go on better.
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.
14th December 2010: Dress I'm making the version of Yzma with a black dress, feathers around her neck and that weird head decoration.
Here is the dress so far. It took two nights, following a pattern. Her dress actually is far strappier than this, and also more hourglass in shape, so adjustments will be needed. I'll do what I can but I can't make myself be shaped like Yzma so there will be compromises. XD
Also, it doesn't look that way in the photo but the dress is quite long and pools around my feet a bit the way Yzma's does.