Do you have young children?

You may be able to train them to be young librarians, and to be able to put their own books on the correct shelves.

You might code the books with colored tape. This will be far from an elaborate classification system, but it may be suitable for your young child.

Instead of the shelf numbers recommended elsewhere in this website, you might use one color for Chumashim, another for Siddurim, another color for Mishnayot, and so on. Be sure that the height of the shelves is low enough for the children to access them easily.

Train the children how to put books back on the shelves. The children will feel big when they can shelve books all by themselves.