Flip the fabric over, wrong side facing up, and fold it in half. Then find the center at the fold and cut slits to make a hole for the head. I just made a horizontal cut across the fold and then a vertical cut on one side to make the head hole large enough for a toddler's head to fit through.
Next, fold the bottom of the fabric over by about an inch and hot glue the bottom edges upward. This will give you a finished edge at the bottom on both sides.
Now, using a needle and thread or a sewing machine, sew the sides 2/3 of the way up starting at the bottom. Leaving the top 1/3 open for the arms to go through. I triple knotted each end (at the beginning and end).
You can see that I did a pretty rough job on the hand sewing. I was going very fast, but wow - not cute! Luckily, you won't see any of these when it's finished. So it doesn't really matter what the stitching looks like.
Set the body aside to work on the wings...