Select a few recent books that share your audience, subject or reading experience. Notice their length, subtitle, cover language and the way they describe the reader benefit. Strong comparisons are specific enough to guide decisions but not so close that your project appears interchangeable.
Use what you learn to sharpen your own promise and identify a meaningful difference. Comparable titles can inform a proposal, cover brief and book marketing plan. They are research tools, not guarantees of sales or substitutes for understanding your particular readers.