Never having done a Swan Lake tutu, my advise might not be good, but how about cutting a few strips of tulle or net or whatever you are using and make them dagged, then make the next slightly longer & so on until you have covered enough of the tutu. I am not sure if thats what they have done in the attached picture, but it might inspire you. Alternatively, you can buy ostrich feathers and just sew them into a wing shape.