Here's how I made my dress.
Then came the Taylor Swift inspiration.
I found this fabric that was perfect for what I had in mind for the belt.
I searched for black sequin fabric and didn't find one I liked. I did find a dress on overstock.com for $25. It was a few sizes too big but I knew I could take it in. I originally planned on cutting the top off and using it. But, when it came in the mail and I tried it on I liked it as a dress. I ended up being able to keep the dress tucked under the skirt of the bridesmaid dress. Yay!
I also can use the bottom portion of the dress as another dress when pulled up and belted. 3 dresses in one! For less than $30!