Graphics, colors and words are the three elements of cover design.

When designing a book, we must combine them organically according to its nature, content, use and readers, so as to show the rich connotation of the book. Follow the modeling rules of balance, rhythm and harmony, highlight the theme, boldly imagine, and use the knowledge of composition, color and pattern to design the cover, which not only conforms to the content, but also makes the reader have a sound.

I hope the answer can help you.