I folded the fabric in half long ways and sewed the end. This would become the side seam for the skirt. I then choose which end would be the bottom of the skirt and hemmed that about 1/4 inch.
(As a little tip: I ironed the fabric to help keep my lines straight.)
Ta Da! I now have turned a onesie into a dress for only $2 and about 30 minutes of my time.
Then to see how I made the fabric flower as an accessory for this dress see my tutorial here.