Always reply to a woman even though you are not interested in more conversation. If you don't reply or go offline when she expects a reply, it will definitely leave a wrong impression about you personal etiquette.

If you want to ask her for her phone number, be very tactful and tell her you would love to listen to her voice if she doesn't mind. Avoid being very direct and blunt as women hate stubborn questions.

Do not get too personal with her if she is letting you know some of her secrets. Be patient and a good listener.

Be honest with her and build those ground of mutual understanding that will make her feel that you too confide in her.

Don't talk about sex before she starts the topic. As it is a very sensitive and personal issue, it's always the girl's side who will want to do the talking.

If she is not interested in you don't keep mailing her to act desperate, mail her twice and if she doesn't reply, get the hint and move on.