Whyislife had a question about how to make the criss-cross detail on a dress she would like to recreate and I thought it was such a nice detail that I put it on a barbie dress!
Hopefully this makes sense:
1. Sew tulle/chiffon/whatever you are using to the back opening of your dress before the zipper or buttons
2. Cross them over and then back again
3. Sew them back down to the back edges, it might be best to baste them on while the person is wearing the dress for best draping effect
4. You might want to finish that edge with bias tape, but thats just my opinion.
There we go! Ignore the barbie, she isn't in her prime anymore! She belongs to my 6yo daughter and has seen better days lol!
Anyways, I hope that can help someone. I also wanted to say that bias cut chiffon or some other drapey soft fabric would be better than Tulle, it was very stiff to work with and didn't drape nicely at all.