I show an interest in them.
It's both that simple and that difficult at the same time.
Every one of us wants the same thing, we want to be wanted. We want others to be interested in what we are interested in, what we are doing, and what we care about.
If I want my students to be interested in "what I care about" (my classes), then I have to show that I am interested in them.
But it has to be genuine. This doesn't mean that I have them fill out a survey about their hobbies. It means that I spend time every day, intentionally, trying to learn FROM my students.
Once that positive student - teacher relationship is built, the rest becomes quite easy.