I was going through my linen closet awhile back and found a whole bunch of pillowcases that I never use anymore. For the dress, I just added the embellishments that I had hanging around. It was easy, just cut and sew the seam. I also added one to the middle and a bow to the back. For the sleeves, I just cut an armhole and sew in some stretchy stuff in to the collar. The sleeves were so easy too, just cut and sew.
The superhero cape was even easier! Had some free ribbons and sewed them on. Made different letters "H" for my daughter and "S" for my son. They love them! Have given them away for gifts too and it's great!
I am not the best photographer. Would love to be, but my camera is just point and shoot!