This may be years too late, and probably you wont even see my reply, nevertheless, I just have to second the part of wildeabandon's reply about smiling to people you have a moment of eye contact with.

It might feel silly at first, and it sure doesn't need to be long and strange, just a quick smile if you and another catch eyes for a second. Try it out, it's easier when you dont know them and they/you are on the move.

Jx