After purchasing the right sized lined crochet tutu top, I took rolls of 6" wide sparkle tulle and cut into lengths twice as long as I needed each to be. I sewed 2 inch wide (by 7" lengths to allow for seams) ribbon along each end of the tulle strips. (You *could* forego the ribbon along the ends, but I LOVE the result.) I carefully rolled each length of tulle lengthwise and then twisted it at the very middle of the length. I threaded the twisted middle through each "hole" in the bottom of the crocheted top.
Once pulled through, I pulled the 2 dangling ends through the new loop. Repeat this in the same exact direction until the entire bottom of the top has been finished.
I added ribbon straps to the top, and the dress was complete. I sewed a small Tiffany's jewelry bag to the finger of one of her satin gloves, added a handmade necklace with a brooch, sunglasses and a tiara.
Updated 11/1/2016 - She loved this costume so much that she wore it again this year!