Breaking the ice

At a con I've found its really easy to start a conversation with someone wearing a cosplay you know. Chances are they liked the show and if you like it too its easy to start a conversation that could transition into something else. Anywhere else, I'd say the best way to start is with a genuine compliment. It seems silly to say you like X if you really don't.

Cons are the easiest to break the ice, you can approach in many different ways either by complementing on their cosplays, if they are in line with you asking what time is it then seeing how excited they are. So many possibilities and senarios.