Spacing
There should be sufficient room on each shelf to accommodate the end brace and extra space for book re-shelving. Sometimes a shelf looks almost empty. This can be because many books from that shelf are in use, but often it is the result of haphazard re-shelving. Leave an even amount of space at the end of every shelf--usually about 1/4 of the total shelf space. Do not crowd shelves or cramp books!