If you're trying to learn the system and what not to do: just show up, be prepared to give your best, do not be selfish with your time, do not lie. Always do everything with good intent. If you mean well and truly f somethign up, you'll be ok. But if you have a bad track record then you're going to start running into trouble. Show up in peak physical and health condition.
If you're asking because you want to hear stories about D-Bags, well dont knock it until you tried it. OCS will teach you a few things about yourself. Its not for everybody. Then theres the times where your body will betray you. You can be in the best shape possible and sometimes things just go snap. Do your best to maximize the odds though and kick ass all the way through