Pretty much what ichigo said is some of what I did for Panty and Stocking. I actually found a pattern
that I used for the bodice of Stocking because I didn't want a separate corset. It took some modification to do some of the detail work, but it was easy enough to do. I then added a circle skirt to the waist for her. The blue detail on the skirt was bias cut so that it curved around the circle skirt easily.
For Panty, I used an old pattern
I had from years ago for the skirt and one for drafting the top
. I don't know if you would be able to find those patterns anymore, but they are the ones I used. For the skirt I used the option with the two layers of ruffles and then just made a long piece that draped on the front and hand stitched it down. For the top I used one of the halter shaped ones, added the band around the bottom, and then just worked with the gold vinyl to get the shape of the collar I wanted, then cut the top and put the gold on. I cut two collars of gold so that it sandwiched the top between the layers and left no raw edges.
For the hearts on our costumes I bought clear heart shaped ornaments that have two parts at Hobby Lobby and then painted the insides of them the right color, filled each half with expanding foam, and then cut that off, put a thin, smooth backing on them, painted that, and then attached pins to them so that they could be removed from the costumes if we needed to.
Here's our costumes
(we did some extra colors on them so that they wouldn't be boring and just plain white). Ours were made of dull satins and stretch vinyls. My stocking were a mix of stretch lycra and stretch cotton jersey and both of our gloves were stretch lycra. I'm also doing both of these on commission for a few girls as well with all the color accents that we did on ours.