1. Pay for coaching (I would recommend this if you're serious about getting this skill down.)
2. Find a mentor. <---If you choose this route, it's necessary that you be able to bring some sort of value to him. Either he has to like hanging out with you, or it would be an exchange of services (e.g. say you know how to play piano and he wants to learn. You could teach him to play it and he'll teach you to get girls).