just say hello.
A 'mission' i read somewhere on this site im sure, was to say hello to EVERYONE you meet in an afternoon, or a day, or whatever time frame you give yourself.
Men, women, young, old, working, not working, doesnt matter, say hello. get over it.
Sure people will ignore you, some will say hello, some will not hear you, some wont care enough to reply.
They're just as scared as you are.
EDIT
approach tips:
* from the front, never from behind.
* you have 3 seconds from eye contact, else you come off as creepy/desperate. save for something like "excuse me miss, you dropped this" *object* perhaps you could use it as an open, but you already lost your chance, you probably wont use it anyway.
* smile and say hello
