Since I sometimes have trouble with fit because of my narrow heel and wide toes, I prefer a shoe with an ankle strap or one that criss-crosses over the instep for smooth. If you don't like that look, you can buy a plain pump (the ones with elastic sides stay on pretty well), and use a clear plastic band (on-line shoe stores almost always offer this accessory) over the instep for extra security if needed. The fit of the shoe is key.