OCS is set up much different (read: better) this year than it was last year. Not saying it was easier, but different. Last year there would be several graded physical events on back to back days with no time to recover. This year we had our graded events spaced out. Plus, on post-hump days there was no PT, we were usually in running shoes, and we would have 30-45 minutes scheduled to go stretch with the PTI. That seemed to help more than you might think. Also, ice is available at night, usually after lights out. Almost everybody in my plt had something they wanted to ice. Stretch in your rack before you go to sleep and if you wake up early enough in the morning, do it again.
If you've had problems with something in the past, get screened by physical therapy at the beginning. They can help you out and give you tips and stretches to help keep from screwing yourself up again. Make sure you have new shoes and boots and new insoles. I finally figured out that my faithful old black boots were the devil as far as injuries.
That's about all I can think of. I'm sure other people will have more ideas. Good luck!