Rule #1: On your first day in prison find that largest guy you can find and go up and start beating the shit out of him. You will lose the fight badly and go to the infirmary, but the other prisoners will think you are bat shit crazy and not to be effed with.
I definitely would not advise that. A lot of prisoners actually
are bat shit crazy, and by doing that you will just make yourself a status target. If you want to survive prison be as low key as possible.