Decide on a general topic first, and then choose a subtopic. A general topic may be "healing after a divorce" while a subtopic will address specific issues, such as "learning to trust again" or "examining how to let go." Working in stages may help you narrow down your choices and pick the best one for your particular situation.
Visit a bookstore and walk around several areas, including the self-help section. Stroll through the personal improvement and new age/spirituality sections as well. Depending on what your beliefs and needs are, you may find the right book in a strange place.
Research self-healing books online. Psychologists, therapists and doctors often publish books based on their own techniques and experiences. Understanding what the different schools of thought are out there may make it easier to select a book that is right for you.
Select a book that has received good reviews by both the critics and the public in general. You want a book that is well written, but also has an impact on the average reader. A well-written book means nothing if it doesn't actually help those who read it.
Ask for recommendations. If you know a therapist, ask her for a list of self-healing books that can help in your particular situation. A professional may best understand what you need and how to help you select what works.