Instead of reading for content or to better understand the ideas in the writing (which you will automatically do to some degree anyway), you are trying to understand how the piece of writing was put together by the author and what you can learn about writing by reading a particular text.
The ability to understand Historical events requires a different skill set than the ability to put those understandings into words. historical study is saddled with the expectation of years of compiling data and research. To even pursue higher education it is required to do so. Learning how other Historians and individuals put their thoughts and research into an essay or collection is one of the most important weapons in a Historians arsenal.