What you will need:
6-8 yards tulle (more tulle = more poof)
1 Spool ribbon
1. Measure: A tutu hands on the hips, so using the measuring tape to determine your circumferance at your hips, not your waist, then add an additional foot because you will need 6 inches on each end to tie a bow.
2. Cut your ribbon to the length determines above. For example I am a size 8 with 38 inch hips so I cut a 50 inch piece of ribbon to be the base of my tutu.
3. Measure again. This time, measure from your hip to length you want the tutu. Personally, I want my posterior covered so I error on the side of modesty. Besides, you can always trim it shorter.
4. Cut the strips of tulle double the length you want and 3-5 inches wide. A good tutu length is 14 inches so the tulle would be cut in 28 inch trips. (Helpful hint: Folding tulle makes it easier to cut.)
5. Knot tulle strips onto the ribbon base. Fold the strips of toile in half. Loop over ribbon and pull loose ends through. For a more full tutu alternate your knots. Add strips of ribbon for additional flair.
6. You got it, now flaunt it.