I decided to be a ballerina for halloween and created my own Tutu! Here is the pin from my board that I found: http://pinterest.com/pin/152840981075268343/
-If making for an adult, measure the elastic around your waist, and make it a little larger than your waste just in case. Instead of sewing the ends together, attach with a safety pin for easy adjustments.
-Also, several sites tell you to use 1 roll of tulle. I used two 25 yd rolls of Tulle for my tutu. It made it look more full and presentable =)