This was my first attempt at a "modified" pillow case dress. If you aren't familiar with those, essentially you cut the pillowcase to length and just "finish" the top leaving everything else alone. I figured it would be easy enough to sew two rectangles together and hem it so I went with fabric I liked instead. This also allowed me to control the width better.
I used a combination of two websites and their versions as well as one of my daughter's dresses for measurements. The top part is elastic (used to be as wide as the bottom).
1 Yard of Fabric (I used 1/2 yard for her size)
Rick Rack (which is just a silly name)
and of course thread, pins and patience :)