A short brief that gets useful drafts back: shelf, promise, constraints, references and deadline.
1. Name the shelf and the promise
Start with where the book will sit and what the reader should expect. 'A literary thriller for readers of cold, atmospheric crime' tells a designer more than three paragraphs about the plot. Then state the promise in one line: what feeling should a browser get before reading the blurb?
2. List the constraints, not the taste
Give the trim size, the title and subtitle exactly as they will appear, the author name, and the delivery formats you need. Mention anything that cannot change, such as a series typeface or a publisher logo. Save your aesthetic preferences for the reference step; they are more useful as examples than adjectives.
3. Send three references with a reason
Three covers that promise something similar, each with one sentence about what to borrow: the type scale, the palette, the way the subject is placed. This prevents the designer from copying a cover and helps them understand which part of it matters to you.
4. Agree on rounds and files before the work starts
Say how many directions you expect, how many revision rounds you will use, and what the final delivery includes: front cover, full wrap, 3D mockup, and the source file if you need to update a title later. Agreeing this up front is cheaper than adding a wrap after the design is finished.
File sizes live in two places: the print cover measurements has the full wrap for each trim, and the calculator turns your page count and paper into the spine width.
cover size — A brief that names the trim saves a revision round later, because the cover size follows from it.
What to do next
Open the free cover generator to test a direction, then run the cover size calculator for your trim and page count before you export. If the file still is not right, the design services page lists what a human pass covers. The guides index has the rest of the process in order.