I put nothing inside besides books (Not counting my backpack and coat). They stay at the bottom of my locker like library books in a library.
I don't even have a locker shelf or one of those magnet things that you stick on your locker and put pencils and stuff in. Nothing but books, backpack, and coat.

Hope this helps!
(just kidding)

For me, I find that simplicity helps me keep organized. Locker shelves makes me feel like my locker is cluttered, same with sticking papers/wallpapers and things on the locker. I find that it helps to keep notebooks and looseleaf paper in my accordion binder, with each corresponding subject. The most important thing is to never leave papers and other junk laying about the books in the locker. Not only does that look bad, but you can damage your books and pull out random junk when you just try to find one book, not to mention loose a lot of random stuff in your locker. Rule of thumb: Never throw papers in the locker. As my elementary school math teacher always said (although it was for something mathematical and had nothing to do with organizing):
Keep It Simple Silly!

(I hope that helped)

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Ello, i can haz cheezeburgerz - me iz spekith engrish! - ok dis randum.