Keywords are what people type into search engines when they look for answers. Understanding them helps you identify what readers are already searching for.

Use free or affordable keyword tools such as Google Keyword Planner, Ubersuggest, or AnswerThePublic. 

Type in words related to your field and see what variations come up.

For example, if you’re writing about stress management, you might discover that thousands of people search for “how to stop overthinking” or “quick ways to calm anxiety.”

Those phrases show not only what people want to learn but also how they describe their needs. That language can guide your book’s title, subtitle, and even chapter names.

Keyword research also shows you what topics have consistent interest and what might be too narrow.

A topic that gets no search traffic might not have a large enough audience, while one that gets massive search volume might be too broad to stand out.

Look for middle-ground keywords that show real demand but still allow room for your unique perspective.