Dress up plain flip flops with paracord. Use the same method that you'd use for a bracelet, but use the strap of the flip flop for the center. The tutorial in the attached link shows how to make them by completely removing the strap.
I bought theses Mickey Mouse flip flops at Disney World and couldn't walk in them for long at all! The hard rubber strap hurt so bad! No heart to trash them since they are Disney so I found DIY Slingback sandals! I put a super soft stretchy fabric in place of the painful rubber thing and now they are my most comfy cute casual sandals perfect for Disney!!!!