Look, I'll be 100% honest, I know it will sound bad but believe me it depends on the woman. Is she super hot and beautifull? Don't. She already got a lot of attention all the time and she won't be nice. maybe she just want a nice time without men aproaching. Is she very obviously ugly woman? Just say hi. Adjust your action according to the beauty spectrum.
Is it stupid? yes but it's true.
Feet fetish is a mistery I will never understand