When I saw Ruqayyah Davis' Pompom Sandals I immediately wanted to do something like it, but I didn't like the idea of attaching anything with glue to my strappy sandals. I also wanted to be able to change the shoe-accessory, or to put the pompoms on other shoes. So here is my soultion - a removable pompom shoe accessory.
Measure the length between the straps. For me it was 15cm (6"). For the loops, add 6-7 cm (~2.5") on each side. The total length is about 28cm (11").
Cut 2 pieces of black elastic that length.
Mark with pin where to fold to make the loops.
Fold where the pins are, and sew the end of the elastic , to make a loop.
Make small pompoms (I used the fork method, there are tons of tutorials for that), as many as required. When securing the end of the pompom, leave a tail long enough to be able to sew the pompom onto the elastic strap. Sew the pompoms along the strap. Don't cover the loops.
To attach to the sandals: insert the loop underneath the sandal's strap, and then over the first pompom. Repeat for all other loops.