Once you have sewn it, turn it right sides out and sew it for a nice finished look.
Sew on velcro or just leave it as is for tieing.
You can also add a fun detail to the back like I did. I added her initial as well as some rick rack I already had in my stash. I uesd the open part of the pillowcase as my guide for the rickrack and sewed it on, closing the bottom of the cape.
You can tie the cape on....
or you can use the velcro.
Not bad for a 10 minute project and endless amounts of fun for your little one.