My biggest piece of advice is pay attention. On your first day you are going to be overwhelmed and confused. Instead of stressing out and lossing focusing use that energy to take in as much information as possible. You are going to be required to not just memorize but what people are saying but you are going to be pushed out of your comfort zone and people might even expect you to do things/know things you have no clue about. You have to think on your feet. The answers might not always be right in front of you, sometimes you have to get creative to figure out a situation.
My second piece of advice is don't worry to much. On your first day you might feel so lost but by your second week you feel like a pro. Once you get the hang of things its really not that bad and you feel this sense of pride and entitlement. Especially when you get your own walkie talkie.