While I am listing this last it is important to start this step as soon as possible. Start working out and start memorizing the information that you will be required to know. OCS requires that you be in excellent physical shape. Scoring well on the APFT is a must both when you start and when you complete OCS.

If you want to know what are solid scores check out this APFT calculator. Check out the Valuable Links section for sites with more information about preparing for OCS.