When I "inherited" my classroom, I also "inherited" a classroom library that needed a lot of TLC. eBay and yard sales helped me add quality books without breaking my budget. The next order of business was to organize the books in a way that made the books easy to find and hold the students accountable when they borrowed them.
I created a simple excel spreadsheet of every book title and author in our classroom library. I printed out the master list so the students could easily peruse the titles. (We keep this master list with our classroom library.) Then, I printed library cards to go in the back of each book.
When the students checkout a book, they fill out the library card and place it in the basket. This holds the students accountable for the books they have borrowed. It greatly reduces the number of books that are misplaced throughout the school year. The students sign the book back in when they finish reading it.