Review the text, paying particular attention to passages you marked. Locate the passages that contain material you can reasonably use to support your thesis.
Gather authoritative extra-textual support documents if you plan to use any. For example, if you plan to propose that a character is schizophrenic, you may want to use the "Diagnostic and Statistical Manual of Mental Disorders" to support your point of view.
Rough out a first draft. If you need to, leave blank spaces where you will insert support. A rough draft will help you to narrow down what support to use and where.
Paraphrase or summarize relevant passages from the story or poem for your reader. Do not give the reader a full rehash. As you need them, include only those elements of the story that support your thesis and that your reader needs in order to follow what you are saying. You do not use quotation marks around paraphrased material because you have recast it into your own words. However, for this type of reference and for all references, note the page numbers in parenthetical citations in the manner that your citation style requires. The Modern Language Association style is usually preferred for literary criticism.
Quote important lines if they support your argument. To quote, use the exact wording from the text and add quotation marks. Explain why they are germane to your argument.
Mention symbols, motifs and descriptive passages that support your thesis. Explain how they support your thesis.
Mention passages from the story or poem that seem to contradict your thesis, and explain why they really don't contradict your thesis or acknowledge that they do, but that the body of evidence more strongly suggests your thesis is correct.
Pull in any material you need from your extra-textual sources. Use these sources fairly. That is, do not take something out of context and misrepresent the author's intention in order to support your thesis.