Before folding, I stiffened the fabric using the same technique that I use with paper: I laid the fabric squares on top of an acrylic plate, painted it with a Methyl Cellulose solution, and let it dry overnight.
The Sunflower is a model created by Nilva Pillan. The instructions can be found in the book, Doctor's Origami Dream Book, ISBN 9784255003788, by Toshikazu Kawasaki.
The Party Dress is model created by Alison Reisel. The instructions can be found in the book Minigami: Mini Origami Projects for Cards, Gifts and Decorations.