The long blue gown was the first thing I started in this costume, and i recently finished the top of it. I found a semi-shiny royal blue color fabric that was on sale, $4 a yard, and bought 5 yards. Decided to make a 3/4 circle skirt, since a full circle would make a really full skirt and I don't want it that big. The width of the fabric is 45" (JUST enough for it to reach the ground for me. I'm 5'3.  So adjust accordingly how long you want it).   I folded the fabric 3x at 45" and cut off the excess. This used 3.75 yards of fabric.  Using a piece of string that is 45" inches long, tape it down at the bottom left corner.  Move the string from the top left to the bottom right, marking it with chalk as you go.  Cut along this dotted line marking.  Open up the fabric and connect the 2 ends and sew!