To achieve a higher degree of charm, laugher always works well. The more you laugh and make the other laugh the more you will charm the other person. People like funny things (makes them happy) and it helps bringing down “the wall”.
Depending on their interests (which you should already know by now) try to share funny pictures or videos, introduce them in the conversation. Try to keep it clean, unless you both seem to enjoy a more naughty sense of humor (use discretion; be smart!).
Making the other laugh should be easy and come naturally. Stay away from boring things like work or past relationships. If the other person starts sharing this type og information and you see that the conversation is moving towards a darker path, try to change the subject and talk about something fun.
You can directly tell the other person, “I know that felling and I share your pain on that subject, but I would rather not bore you with this at the moment. It’s not that I’m not interested, it’s just that I want to know the fun you and share a good time, life is full of bad circumstances, but you make me forget them and I would like to share fun memories with you instead of sad ones.” I know it’s a long phrase to memorize but you get the idea. I’m sure you can find a way to discuss fun things and stay away from the bad and boring memories.
Women tent to share bad stories and regrets more often than men. Sometimes I think it’s a test to see if us men can bring them back to happiness, but that’s just my impression. So my advice to you is to keep the other person interested and sharing fun and good memories with you. In the end, when they think back to the conversation, they will remember that they felt good during the conversation and they had fun. This will make them want to see you again cause they had a good time.