>>11777841If you're already in university and have a good relationship with your professors, talk to them about grad school. They always give their own advice and mention universities, professors and research groups that they might find relevant. Of course, you have to tell them what, exactly, you're interested in studying.
There are three other things, too. The first one is about attending to conferences, watching presentations and talking to people from other universities. You get to know who is who and which universities seem to be good at what. The two other things are taking grad school courses and doing undergraduate research. You will inevitably be forced to read a good amount of literature from your field, and you might end up noticing that certain universities and professors are more expressive in it.