D.T.
I made some really cute and easy ones for my softball team in college. Just get any type of fabric and cut it into strips using pinking shears. I think I did 4" long by 1" wide strips. Then you just tie them around the straps of the flip flops. The more strips you use the fuller and better they look. I alternated fabric colors (blue and white) for our school colors. Hope this helps- have fun!
D.