Business cards are good if you have not had time to build any chemistry or banter but feel there is some attraction there. Just hand out your card and say something like 'well nice meeting you,if you want to continue this chat sometime contact me'. It costs you nothing and you will be surprised how often it works.
Sometimes it doesn't seem right to ask for a girls number if you have not had any time or managed to get a connection or she is with friends etc. Say standing in the queue at a supermarket in your lunch break. Hand out the card and see what happens. What's the worst that can? I find it works well on flights with chicks you have sat next to but maybe not managed to enter seduction stage with.
Sometimes it doesn't seem right to ask for a girls number if you have not had any time or managed to get a connection or she is with friends etc. Say standing in the queue at a supermarket in your lunch break. Hand out the card and see what happens. What's the worst that can? I find it works well on flights with chicks you have sat next to but maybe not managed to enter seduction stage with.