Reading itself is an act of interpretation. Your audience, your subject, and your argument are connected. An essay, therefore, will demonstrate how well you express your ideas, how well you can identify a problem, and how well you analyze, organize, and synthesize material. To write professionally suggests that you need to follow certain guidelines, exact rules for documentation, and other exacting grammatical rules. Gathering and analyzing .
Secondary sources are works of criticism.
Remember that it is always better to read an original text and refer to it than to read and refer to a critic who has read it. The more literary texts you read and can refer to the better. You can't possibly read too many. Remember, the key to your essay is the number and quality of your ideas about literary texts. To catalogue random material does not comprise an essay.