Advice to a New Teacher

A student I met a couple of months ago at my university sent me a message via facebook today and asked a question I never expected to answer:
I am going to be teaching for the first time at the uni this coming semester, do you have any advice for a so far non-experienced student lecturer?

This is the response I wrote. I didn't think too much about it; instead I just recalled my own experience as a new instructor:
Well, hmmm... Once upon a time a long time ago I walked into my first classroom as...