Lock in a few goals you want to know first, and then observe their behavior secretly, so that you can know what they will think, and then wait around them. For example, if you are a student who often asks questions to the teacher, you can pretend to ask questions, and then you can have a dialogue with her. Over time, the relationship will develop better.

In short, it is to find out their living habits, and then take the opportunity to get close and increase interaction.

If you think it's too slow, maybe you should run more social occasions, try to strike up a conversation, get their information through dialogue, and then keep talking.