You can do a book report on historical fiction by looking at the author's use of language to create the historical atmosphere. Notice the words and phrases that are specific to the time period. Also, consider the themes in the book. Many historical fictions explore themes like power, class struggle, or love in the context of a particular historical era. And don't forget to talk about the plot's connection to history. How did historical events drive the story forward? This could be a great aspect to include in your book report.
One idea could be to focus on the historical accuracy of the setting. For example, if the book is set during the Industrial Revolution, research how accurately the author depicted the working conditions, the social hierarchy, and the technological advancements of that time. Another idea is to analyze the characters in relation to the historical context. Were their actions and beliefs typical of the era? A third idea is to compare the book's version of history with the actual historical events. This can help you understand how the author used historical facts to create a fictional story.