Getting hired in (state) corrections is fairly easy compared to a lot of other jobs in the criminal justice field. That doesn't mean the job is easy. As someone who has worked corrections and law enforcement, I can assure it is a very difficult career field. There are lots of things you can do to make it more likely to be hired. I cover much of that on my blog. Once you are hired however there is there are three main things you need to be successful.
1. Integrity. You don't have to be a rocket scientist (though it DOES really help to be able to write well), but you do need to be able to do the right thing even if nobody is looking. All law enforcement careers are aberrations from "regular" jobs because you don't just get in trouble or fired when you screw up... You can actually go to jail. It is critical to be honest and keep yourself out of trouble or the inmates will soon have you committing all sorts of policy violations and even crimes.
2. Communication. You have to be able to talk to people. Unfortunately it's not always the same as being able to talk to regular people. Read books on communication. I recommend "How to win friends and influence people." If nothing else it will help with your coworkers. Also check out the infamous yellow book called "Games Criminals Play." It is required reading in many academies.
3. Defensive Tactics. Working in corrections will really help with those communication skills and in theory you would like to be able to talk your way out of anything. In reality, sometimes there is nothing you can do and you need to go hands on. The Academy (and yearly in-service) doesn't begin to give you the skills necessary. I wrote an entire article with much more detail on why you need to do this. It's too long to cut and paste here.