Figure out what the nurses like and you will be their favorite! Do things on time, chart it as soon as you possibly can and make sure things get done right. Be willing to help with even the not fun stuff. You will learn a lot in the ICU and the more you want to learn, the more the nurses will teach you. We have a few aides in my ICU that are in nursing school and they get so excited when they learn something new, so I will take the extra time to teach them or let them help me with something.
In the ICU at night, our aides help with baths, turns, accuchecks, vitals, emptying things such as catheters, colostomy bags, and certain drains and they help us with whatever else we need. The ICU is pretty constant in how busy we are between day shift and night shift, the big difference is the things going on.
Sleeping is different with everyone. On a rare occasion, I will take benadryl if I have a lot of trouble sleeping. I try to keep my room dark and I usually will use something such as a movie for background noise. I always set the timer on the tv so it automatically shuts off.
Good luck with your new job! You will see and learn a lot!