Do you really think your professors, your future colleagues or even your fellow students have nothing to teach you?

This is so important. When looking for a job, make sure you're not the smartest/most knowledgable person there. Seek out an environment with people who know more than you, at least in some fields.

Another big thing (at least for me) is to always challenge yourself. Work on stuff you don't know how to do in advance, things that require you to learn new skills. I find I get bored and burn out quickly if my work is just doing the thing, instead of figuring out how to do the thing.