Empty space is the ingredient

The failure mode in both directions is uniformity. A shelf of identical spines reads as a wall of texture and nothing else; a shelf of evenly spaced ornaments reads as a shop display. What makes shelving look composed is variation in height, weight and density along the run.

Lay some books flat and stand others upright. The horizontal stacks give the eye somewhere to rest and double as plinths for a single object, which solves the problem of small things looking lost.

Leave a third of it empty, roughly. That is the ingredient people leave out, and it is the difference between a styled shelf and a full one. Empty space reads as deliberate; a completely full shelf reads as storage regardless of what is on it.

Work in groups of odd numbers and vary the heights within each group. Three objects of visibly different heights hold together; three of the same height read as a row.

Finally, step back to the doorway. Shelves are arranged at arm's length and seen from four metres away, which is why so many look busy in the room and fine in the photograph taken from close up.