Smile, introduce yourself. Then compliment something about them or their clothing, or if they have a book or are carrying something, mention it and ask them a question. Don’t ask personal questions, try to keep it pleasant and light until you get to know each other. Someone once began a conversation with me with, “I like your red hair, you seem like a creative person.” I told him not only was I creative, but I created my red hair from brown hair. we’ve been friends for twenty years now.