You have a clear physical disadvantage, and a strict set of requirements to attain. You're going to be remarkably dependent on your mental faculties. I am going to categorize these into two categories:
- Observe more information than anyone else, so that you constantly have more information than others to work with.
- Process that information more completely than anyone else, so that you can act on that information without revealing a clear path back to your information (if they ever figure that information out, you no longer have information others don't have).
You are going to have to walk a fine line between identifying clues in your environment which will let you dodge that which you will not endure, while simultaneously not letting on that you're smart enough to do that. If you don't identify enough, you may get pinned in a trap (come to think of it, didn't you mess up bad enough to get trapped in a prison in the first place? Oh bother). If you do too much with that information, people realize just how smart you are, and you become a resource which may be intimidated for valuable intel.
Your entrance to the prison will be the hardest part. If you think about prison as a closed system designed to grind the "bad" out of people, the influx of new prisoners is fresh energy for the bad people to prey upon. Bad things will happen, and it is probably not in your power to stop them unless you're the Bodhisattva from the South Sea with her Treasure Vase and Willow Wand. All you can do is focus on them not happening to you. You will have to rely upon your fellow inmates to take one for the team. You will need to maneuver yourself, both physically and socially, into a position where you are invisible behind someone else who is a better target. You will have to do so in a very balanced manner: the predators will need to see the cannon fodder you let step in front of you, but the poor individual who is preyed upon must feel it was sheer coincidence that they happened to be in front, and you happened to be behind. The only way to do this is to observe enough to see it happening before it happens, and find sly ways to maneuver under their radar.
Moving further into the life in prison, you're going to need some layers of ablative meat padding, also known as "friends." Prison is a dynamic environment, with danger around every corner. Your job is not to make prison safe, its to make your 4 square feet of prison safe, and you take those 4 feet with you wherever you go. You will need to find prisoners who are willing to act to make that safe for you. Obviously you will need to have something to give them in return. A semblance of order might be such a thing (the mafia has this effect on its members). If you can find just a few people who are looking for some peace in this madhouse, and you can make it appear that you can help them achieve this, they may be willing to make your life more palatable.
The details of how to do this, of course, are an entire book. Or perhaps a life time. Wasn't there a book where the Earth was a penal colony for humans managed by extraterrestrials? How do you achieve your inner peace in this mad world of ours?