To make the skirt, I used the dimensions below, sewing where there are dashed lines so that I had a 56″round opening in the center (two times my waist measurement).
Then I sewed my elastic into a tube, making quarter circumference marks on it. I matched one mark to the center back seam, one to each side seam that was formed by the 5.5 inch edge I sewed together, and the last mark lined up with the center front of the fabric.
Stretch the elastic flat as you sew it to the skirt fabric, leaving 1/2″ above the elastic as selvedge.
You can see in the pictures below how the squared off sides make the skirt drape differently from an A-line or rectangular skirt. They almost form pockets.
I sewed the pieces together at the sides and shoulders with my serger (use a zig-zag stitch if you don’t have a serger). Then I sewed a straight basting stitch around the neck and armholes 1/2″ in from the edge.
Then I turned the edges under, so that the basting line was right on the fold. This allows you to stretch the fabric inside the shirt to lay flat while keeping the outside of the shirt unwrinkled. (I hope that makes sense).