I have an employee who did 8 months in the OC prison. Although it depends on where you are, he shared a few of his stories. These may or may not be true and/or exaggerated...
1. Depending on your race, you will be "beat in". The length of the beating depends on what race you are. The first letter of your race is how many seconds you get beaten. Black= 2 seconds, Mexican= 13 seconds, White=23 seconds. He was white so he got the worst of it.
2. If you do something that hurts the population, you will get your ass kicked. This is probably fairly obvious. He said he accidentally removed some dumbbells from the rec room to another part of a prison which was a no-no. The guards took them away from everyone as a punishment and, in return, he got his ass kicked.
3. If you do something that someone who's part of a gang doesn't like, you can be "greenlit". That means you are fair game for anyone in that gang to attack. While this guy never got greenlit, it was always a fear of his because an attack could be when you least expected and you'd be constantly paranoid.
4. Inmates know where cameras are and aren't. While this may be another fairly obvious one, watch where you go. They know where they can get you and where they'll be caught on camera. In general, the guards don't really care so if there's no hard, video evidence, it's hard to prosecute them.
Good luck and godspeed.