What can I talk to a girl I just met? How much is once in a while?

If it is really two people who like each other, in fact, everything is very happy. There is no need to deliberately find some topics, and the time is free, as long as it does not affect normal work and life. Of course, if the other person is introverted, you need to deliberately create some interactive topics, such as interesting experiences at school and work, common interests and hobbies, and make some jokes to deepen feelings.