What makes a book cover sell

1. It has to work at 20mm

Most readers meet your cover as a thumbnail in a list of forty others, on a phone. That is roughly 20mm wide. A cover designed at full screen size and admired at full screen size routinely turns to mud at thumbnail, and the author never sees it happen because they are looking at the artwork, not the listing.

The test takes ten seconds: shrink your cover to the width of your thumbnail, put it beside the current top twenty in your category, and see whether the title is readable and the image still reads as something. We design at that size first and scale up, which is the opposite of how it feels natural to work.

2. Genre signals are not clichés

Readers scan for signals: subgenre, tone, heat level, how literary it is. Those signals live in typeface, palette, imagery and composition, and they differ sharply between a cosy mystery and a psychological thriller even though both are crime.

Ignoring the conventions does not make a cover original; it makes it unfindable, because the reader looking for your book cannot tell it is yours. The craft is knowing which convention to honour and which single one to break. There is more on how that plays out per category on our romance publishing page, where signalling matters more than anywhere else.

3. One idea, not three

The most common fault in first-time covers is that they try to depict the plot. A cover is not an illustration of the book; it is an advertisement for a feeling. One subject, one focal point, and enough empty space for the title to breathe.

If you find yourself explaining why the lighthouse, the raven and the pocket watch all need to be there, the answer is usually that none of them do and the cover needs the strongest one at twice the size.

4. The typography is the design

On most successful covers the type is doing at least half the work. Two typefaces is usually one too many; two weights of one face reads as deliberate, while two faces reads as indecisive. Tracking matters at small sizes, and so does where the title sits relative to the busiest part of the image.

• Give the title the plainest area of the artwork, not the most interesting one.
• Decide the line breaks yourself. A title broken badly looks accidental, because it is.
• Keep the byline at the foot of the jacket, sized for the author you are rather than the one you hope to be.
• A strapline earns its place only if it says something the title does not.

5. Contrast beats detail

In a grid of busy covers, the one that stands out is usually the simplest. An almost entirely white cover among dark ones, or a single point of saturated colour in a muted field, will out-perform a beautifully rendered scene every time at thumbnail size.

6. Your face is probably not the cover

This comes up most in business books and memoir. A portrait on the front dates quickly, reads as self-published at small sizes, and spends the cover’s only focal point on something the reader has no reason to care about yet. The author photo belongs on the back cover and the author page.

The exception is a genuine public profile, where the face is the product. If people already recognise you, the usual rules do not apply.

7. The spine and back cover are part of it

Spine width is a function of page count and paper stock, so a cover cannot be finished before the interior is. Change the text after the cover is built and the spine no longer fits the book — which is the most common reason a cover is paid for twice.

The back cover needs the blurb, the barcode area, and restraint. One endorsement band reads as confident; three columns of praise read as anxious.

8. One design, several crops

A finished cover is a file set, not a picture: a wraparound print PDF sized to your page count, a square ebook image, a square audiobook image, and the layered source file. Each crop needs deliberate framing rather than a square cut out of the middle of the print cover.

Insist on the source file and the asset licences. Without them, every future change — a new edition, a series re-cover, a promotional graphic — starts from nothing. That is part of what we hand over with book cover design.

9. If there is a book two, design the system now

A series needs a repeatable layout, a colour logic with room to extend, and a title position that survives a two-word title and a seven-word one. Retrofitting that onto a standalone cover usually means redesigning book one, which authors discover at exactly the wrong moment.

How to brief a designer

Four things make a brief useful, and none of them is a description of your plot:

1. Three covers you wish were yours, and one sentence each on why.
2. Two covers in your category you dislike, and why. This is more useful than the first list.
3. Your genre and subgenre, and the reader you are writing for.
4. Anything non-negotiable — a series look, a cultural detail, a scene that must not appear.

Then let the designer design. Choosing a direction and asking for two rounds of refinement produces a better cover than mixing two concepts, which almost always produces something worse than either. If you want our view on your current cover, send it with the manuscript — the feedback is free, and we will show you rather than argue, usually by putting it beside your category page at the size readers see.