A common thing u will hear is: "But I have a boyfriend so we can only be friends." U need to ket her know that her attempt to steer the interaction is not going to fly with u. Say, "Well, how about you do what  u want to do and I'll do what I want to do. Hopefully its the same thing, but if not, its not a big deal." Let her respond then add "U can classify things if it makes u feel better, but I like to take thing only one step at a time, whether it is a relationship or dating or anything else" This sends the message that u are going to do waht u want to do, regardless of what she says. When a girl drops the "I have a boyfriend" line on u, fire off a cocky response that lets her know you dont care. "Good, he'll give you smth to do when I'm not around" or "God, I just met u and u are already telling me about your problems" NEVER ASK A GIRL WHETHER SHE IS SINGLE OR NOT.