Bring 2.5 gallon ziploc bags, a few quart ziploc bags,and a few gallon ziploc bags.
You'll need them for the FTX when the waterproof bags they give you inevitably have 30 holes in them.
Bring lots of quality pens and sharpies.
Also, I'd bring a book on Greek mythology and tell them that is you religion so you have something to read. EVERYONE will have a bible to borrow.
Also, dont bring a large amount of clothing aside from underwear, you will IMMEDIATELY change into army PTs and ACUs
Dont bring key locks, bring locks that are combo based but not the traditional school locker locks bu something like this.
Its MUCH easier and faster when you're forced to change uniforms 50 times.
In you notebook write down lyrics to a bunch of songs to keep your mind off things. I only got mail twice during basic, you'll want something to mentally disappear.
Edit: disregard all typos
I recommend this or similar. Easier to open under stress than traditional combo locks.
Plus if you catch someone stealing, lock inside of a sock properly applied will put an abrupt end to aforementioned thievery.