Ribbon or elastic
You can use what you have on hand as far as width goes if you need to purchase, satin ribbon is the best choice as the knots can be easily moved around, with a width of about 1/2 or 7/8 of an inch. The wider it is the bigger the bow will be when tieing the tutu on. I used 7/8 width grosgrain ribbon because I had some on hand and it worked great.
here's where it gets fun, pick whatever colors you love and don't be scared to get crazy!! I used pink purple and white (not so crazy, but it's for my little angel :) I bought about 5 yards worth which was more than enough for my toddler.
A good pair of scissors
1) Start of by taking your ribbon and measuring around the waist of your subject. Make a mark on each side where the wasit ends, then add a little more length to make your bow.
2) Decide how long you want the tutu to be and cut your strips DOUBLE that length as you will be folding them in half.
3) Now to start knotting. You will be making slipknots. Take your strip fold in half with the loop held to the wastband. Now take the two tails that are hanging and put them through the loop and pull tight. now push the strip to your marked place and continue on till you have made it to the second mark. If you want a really full skirt be sure to push the strips really close together. It's very forgiving so if you make a mistake just keep going, you likley won't even notice.
4) You are now ready to tie on your tutu, and Voila you're finished!!!