If you can talk to her, that's best, and you'll have a chance.
If you can't talk about the topic in depth, you can also look at the people who are close to her, what are her characteristics and preferences, and start with the people around her, so there are many more opportunities to get close to her. It doesn't matter to be friends with her. Go up and say, shall we be friends? If he thinks you are beyond the scope of ordinary customers, he can naturally be regarded as a friend, mainly because he can keep up with the beat and leave a good impression. And the development after that depends on you.
In addition, you can always know something about him in private, so don't chase her even if you don't know if she has a boyfriend.