Silver or clear rhinestones will work with just about any shoe. You can also use colored rhinestones, but make sure that they look good on your shoe. You can use rhinestones that are all the same shape and size, or play around with different shapes and/or sizes.
How do you get Gems to stay on shoes?
https://www.youtube.com/watch?v=l6U9WrjwahU
How do you embellish sneakers?
https://www.youtube.com/watch?v=-9ZO85mQsyc
How do you attach rhinestones to shoes?
https://www.youtube.com/watch?v=KqI8Fd02thc
What kind of glue do you use to put rhinestones on shoes?
Apply GemTac glue as outlined in Applying rhinestones to Fabrics and other items. Set stones, one at a time, into glue. Sizes 16SS is the most common sized used for Flip-Flops. Often, two or three rows are used.