The cover illustration is the first thing a reader sees on a book. It is the first and most important visual representation of your work and should be carefully considered.
The cover art has three roles: it should reflect the genre, reflect the tone, and provide a clear understanding of what to expect from the book.
It is critical that your illustration corresponds to your content so that readers know they are getting what they signed up for. A lot of illustrators focus only on one or two of these elements, but you need all three for a successful cover illustration.
A good illustration will also include an eye-catching typeface and typography which will help set up expectations for readers as well as establish branding for the author’s identity.