Arrange a shelf with a little breathing room
Begin with the things you actually use. Put frequently opened books within easy reach and gather small objects where they can be picked up without moving everything else.
A shelf does not need to be filled from end to end. A little open space makes the arrangement easier to read and leaves room for something that arrives later.
Live with the arrangement for a few days before changing it again. The places where objects naturally return often tell you more than a carefully staged photograph.