Here's a sketch of the original skirt.
I fell in love with the fabric - a soft green corduroy with black embroidery and sequin detail. It was about a size 20 and so there was lots of extra material to play around with. Originally from M&S but I bought it from Oxfam for around £4.
There are 3 main pieces to the dress. Areas cut away from the fabric are shown in red below. (Click on diagram to enlarge.)
I used the excess fabric to create the top piece of the dress (C). It joins the skirt (B) at the back and then comes up over the shoulders and joins to the bust piece (A) at the front. I also reused the zipper in the side seam and the original lining on the inside.