Choose a book to write about. If possible find a book that interests you. If you admire the Tudor period, look for books that explore the reign of Henry VIII or Mary I. If you are drawn to the Civil War period, consider books that walk the reader through the life of Abraham Lincoln or Stonewall Jackson. A book set in a time frame that you find intriguing will be easier to understand and write about effectively.
Research the subject of the book. If your knowledge of the time period the book covers is scanty, consider reading other materials about the time frame in question. Even if you feel well versed in this particular subject, a complementary book can help you gain additional insights. For example a book about Franklin Delano Roosevelt can help you better understand a biography of Winston Churchill.
Read the book at least twice. An effective book review will demonstrate an understanding of the book's nuances and small details. Read the book once to gain an overall impression of it. Read it a second time to pay attention to more subtle arguments and use of devices such as footnotes and sources.
Take notes. As you read it open a Microsoft word file or a notebook. Take notes about your overall impressions of the book. Use this file to note any quotes you would like to use in the book review or specific passages that catch your attention.
Tell the reader what the book is about. Start writing the book review. The report should give the reader a complete overview of the book's subject, including the time period in question as well as the subjects addressed.
Give the reader an opinion of the book. Tell the reader of your review what you thought of the book. Think carefully about the book's goals. If the book set out to explain the causes of World War I or the way in which Queen Victoria's reign influenced history, then let the reader know if the author accomplished these tasks. Let the reader know the kind of language the author uses, whether more geared towards the layperson or towards an academic audience, as well as the sources they rely upon. A good review should help readers decide if they want to read the book.