You mention lectures, which seem to be a bit impersonal by definition. If it's purely eye contact that you're having trouble with, then I would suggest just do it no matter how uncomfortable you feel, and after a short time, it'll just come naturally.
But in the classroom, I think interpersonal skills come into play a lot more. I would suggest you find a teacher you know is good at it, and observe them teaching. I suspect what you'll see is a lot of using students' names, remembering things about their students' personal lives, and asking follow questions during feedback out of a genuine interest. Not only does it show your students that you care, but it can create many opportunities for communication to occur in the future, which can only be a good thing.
