The most direct way is to strike up a conversation, but since you have asked this question, it is estimated that you are not good at striking up a conversation or will not do such a thing. If it's the former, that's fine. If it is the latter, you must first overcome such psychological barriers, otherwise even if you know girls in other ways, you can only be a casual acquaintance at most and cannot become a deeper friend.

If you don't have to strike up a conversation, you can only pass some coincidences. Through some film and television works, we can see the hero and heroine who were completely unknown, because some coincidences can get to know each other. So, all you have to do is create some "coincidences". However, film and television works have scripts and can be developed according to the scripts. In real life, the created "coincidence" is likely to develop in an uncontrollable direction.

When I was in college, all the girls I met were in the school computer room. . . At that time TVXQ!! Very popular. A few girls wanted to play songs, but they couldn't, so I took the initiative to help them play some songs. Another time, a school girl wanted to check the final exam results on the campus network, but she couldn't, so I helped her again. It's all coincidences, but I didn't mean to. Therefore, we should pay attention to the situation around us, and there may be no need to deliberately create coincidences.