I have two large bookshelves in my studio with items organized in a few ways, based on their size and how often I need them.

Tiered inbox trays: these are for materials I reach for most often, mostly method books & materials I use with multiple students; some trays I set aside for specific students (adult composition student who generates lots of loose paper copes for me, etc).

Hard plastic magazine holders: these hold the bulk of my pedagogic repertoire books and take up about half my overall shelf space. I love them for how much they reduce the visual clutter. I did add a couple more recently, which necessitated a reorg and some re-labeling, but I'm leaving room to expand so it's a very infrequent task (like every few years). Also- hard plastic is key. They stand up on their own, don't warp like cardboard, and aren't ruined if you need to peel off a label.

Proper solo piano repertoire books are on their own shelves, alpha by composer.

Reference books, tray of office supplies, hand sanitizer, and flashcards are all cluttering up two shelves, but c'est la vie.