I think people get a little bit too wrapped up in (getting ahead) of the game in what to bring and not to bring. Show up in great shape, pullups are money on the pft but running gets you through OCS. (At least 21-22 minutes in 3 mile). Take care of yourself (don't show up already broken). Those guys go away fast and its happened to at least 2 or 3 people in each Jrs & Srs platoon Ive been in.
These things will make your life easier:
Bring tons of white tape and share it.
A stamp pad
At least on pair of really nice socks, I bought a pair of SmartWool socks that kept my feet completely dry during the humps.
Erasable pens (essays now are so regulated you will barely have any).
The only thing that is a must is the white tape. After a couple of weeks I realized these things didn't really even matter that much. The main things are the things you can't go out and buy at the store:
Be in shape and healthy
dont go to sick call unless youre dying or you really f'ed something up
stay positive and motivated
be helpful to other candidates
don't be intimidated or at least don't show that you are, not by your instructors and more importantly other candidates i.e. proir inlisted
Show leadership but also be a good follower
Its not your instructors that send you home its your fellow candidates. Thats why they have peer evals. If your passing everything but being rated last on the evals, thats gonna skylight you and make your life hell for the rest of OCS
If you do these things and don't fail a bunch of events you WILL graduate.
Thats my 2 cents I hope it helps