Some ways to recognize an author's purpose are to reflect on why the author may have written the text or to examine the structure of the author's work. Additionally, WeAreTeachers states that asking how a text makes one feel or comparing a text with one's own writing are good strategies for determining an author's purpose.
To determine why an author wrote a text, first become familiar with various styles of nonfiction. If the purpose is vague or confusing, review other texts where the purpose is known and compare their elements to the elements of the text in question. Additionally, identify the structure of the text, as structure often reinforces an author's purpose. For example, according to WeAreTeachers, some authors use compare and contrast to put events into perspective, while others utilize sequence to explain events.
Because authors often want their readers to have emotional reactions, simply asking how a text makes one feel and how the author contributed to this emotion is another useful strategy for determining purpose. Also, WeAreTeachers states that comparing the text to one's own writings can be an illuminating exercise. For example, an author may employ an argument or use a phrase that the reader has also used, and this can be a clue for the reader to the nature of the author's purpose.