The process of writing an essay usually begins with the close reading of a text. Of course, the writer's personal experience may occasionally come into the essay, and all essays depend on the writer's own observations and knowledge. But most essays, especially academic essays, begin with a close reading of some kind of text—a painting, a movie, an event—and usually with that of a written text. When you close read, you observe facts and details about the text. You may focus on a particular passage, or on the text as a whole. Your aim may be to notice all striking features of the text, including rhetorical features, structural elements, cultural references; or, your aim may be to notice only selected features of the text—for instance, oppositions and correspondences, or particular historical references. Either way, making these observations constitutes the first step in the process of close reading.

The second step is interpreting your observations. What we're basically talking about here is inductive reasoning: moving from the observation of particular facts and details to a conclusion, or interpretation, based on those observations. And, as with inductive reasoning, close reading requires careful gathering of data (your observations) and careful thinking about what these data add up to. 
 http://www.fas.harvard.edu/~wricntr/documents/CloseReading.html