OCS is a rigorous test and requires preparation before arriving.  The academics will be introduced during class time, but it would be wise to memorize your general orders.

Physical preparation is of vital importance.  The staff at OCS will attempt to tire you through exercise and constant activity.  They will then place you in stressful situations and see how you react.  The more you physically prepare, the less the exercise will tire you and thus you will be more alert and make better decisions.  OCS provides a comprehensive regiment to prepare yourself.  It is also wise to note that most candidates get a lower PFT score during their initial PFT.   Minimize this loss by preparing yourself and not neglecting any portion of the PFT.  The staff is very picky about your Pull Up form and make sure you go all the way down before pulling yourself back up - otherwise they do not count the repetition.