Being a recent OCS graduate, everything that has been posted here is correct. Except anyone going through OCS now, will have it easier. They changed many of the rules. Some of them include:
DI's now have to stay a certain distance away from candidates
No yelling in the chow hall
Candio's can't yell at OC's and can't use knife hands.
...
Also, don't be worried about chow hall procedures. They take some getting used to. But once you're past the first 2 weeks, it becomes second nature. Once you have them down, it's harder not to laugh at the person across from you than actually doing the procedures. Oh, and don't make eye contact with the DI's in the shark tank.