Accepted an offer as a sysadmin, what tips do you have?

I'm leaving a security analyst position and moving to a junior linux system administrator job for a 3 letter agency. I'm pretty familiar with linux since I've been using it for years as a hobby, but never in a professional sense. I was able to answer all the questions and the interviewer seemed impressed.

That being said, what kind of tips would you have for working in that sort of environment as a new linux sysadmin? What should I focus on learning and getting the hang of to make my career as effective as possible coming from no professional linux background?