Know the final trim size
Start with the exact dimensions of the closed book. The cover should be built around that format, not the other way round.
Calculate spine thickness
The spine depends on the number of sheets and the actual thickness of the paper. Paper weight gives an indication but is not always enough: the printer’s paper caliper is more precise.
Compose back, spine and front
On a flat cover file, the back is on the left, the spine in the centre and the front on the right. Text near cuts or folds should stay within a safe area.
Check the final PDF
Check document dimensions, the bleed requested by the printer, spine text position and image resolution before sending the file.
Put these ideas into practice in one workspace
The callen-jf.com Writing Studio lets you move directly from advice to practice: write, structure the manuscript, prepare characters and chronology, then export and format the book. The account is free and the tool remains separate from the public pages of the site.