The first thing one needs to know about creating a critical analysis is the particular aspects a critical analysis examines and details.
The purpose of a critical analysis is where a reader interprets a text in regards to both its direct message and its underlying message. Basically, a critical analysis is based upon the literary theory of Reader-Response.
One good place to start any critical analysis is the title of the text. Here, you would be examining the title "The Yellow Wallpaper" by Charlotte Perkins Gilman (based upon your question posed). By examining the title, one can make assumptions about what is going to happen in the story, the implications made by the author according to the title, and the importance of the image of the object or idea presented in the title.
Next, one should begin the first reading of the text. Be sure to look up any words with which you are not familiar. Skipping over an unfamiliar word can be detrimental to any text and the understanding of the text.
Next, you will need to ask certain questions of the text and your understanding of it. Important questions to ask of a text are:
1. What is the setting? Does it add to the text? Is it important?
2. Who are the main characters? Who are they in regards to characteristics? Do they change over the course of the text? If so, what causes the change?
3. What are the conflicts presented in the text? Are the conflicts internal, external, or both? What comes from the conflict resolution? What happens as a result of there being no conflict resolution?
4. What is the point-of-view? Who is the narrator? Does the narrator's voice illustrate the story properly? Could a different narration be needed?
After posing the questions, reread the text. Look for the answers to the questions posed and analyze the text through these specific filters/lenses.
After, you need to be able to do the following:
1. Summarize the author's intent.
2. State the theme of the text.
3. Justify symbolism or imagery per your interpretation.
In the end, if you find (for example) that the yellow wallpaper symbolizes the physical and mental prison the speaker feels she is in, your job is to support your findings with textual evidence from the text. Be careful not to retell the story--this is not the purpose of a critical analysis. Instead, you are looking to prove and justify your reading of the text and your understanding of themes, symbols, and meaning.