I've done 5 semesters of teaching, and I think the most important thing I've learned is to stop giving opportunities for extra credit.
At first I thought extra-credit and make-up opportunities were a good thing; I want my students to learn and succeed as much as possible. I'm a quick and organized grader, so I don't mind a bit of extra work. I was trying to be compassionate and acknowledge that everyone makes mistakes.
However, I realized after my first semester that extra-credit is a terrible idea. Students use it as a crutch to not work as hard the first time around because they don't feel the consequences of their actions are real. They could be failing with one week before finals and still think "I'll just power through some extra credit to recoup."
Overall, it's not a fair strategy to good students or bad students. I've nixed it entirely.
My stage fright still hasn't gone away though...