Make your own template based on your objectives (what you hope to gain from the book)

For each chapter/ section, note:

What is the main point / hypothesis / argument?

What are the evidence the author uses to support the main point (research, principles, etc)

Was the author successful in persuading the reader?

What's missing from the author's analysis / evidence (this doesn't have to be accurate, your personal opinions and guesses also count. These can be supported/refuted at a later time)

How does the main point relate to previous arguments made in the book?

What references does the author make to other authors/resources (this is good for general reference if you want to expand your knowledge and address the "what's missing" points you made earlier)

All these questions can be modified to fit your needs, and the main idea is to state the central ideas, the evidence, and any thoughts you may have.

If you need more help, consider looking up critical thinking skills online, which should give you an outline of how to think about a given issue critically.