statement that argues a particular viewpoint. The thesis statement doesn't have to provide any evidence for the statement. That's what the rest of the paper does. For many stories, crafting a thesis statement that analyzes a character or a theme is usually a good starting point. The reason for that is that themes are often supported by characters, and characters often introduce thematic elements to a story. In the case of "Miss Brill," I think a good theme to explore is the theme of loneliness and/or alienation. Miss Brill sits is a very public location, yet she doesn't actually engage anybody in a conversation. She imagines herself a part of the world; however, she doesn't take any action that would further engage herself in her world. A thesis statement for this idea could go something like the following statement: "Although Miss Brill imagines herself as an integral part of the world, her lack of engagement with people in the world actually serves to further alienate herself."

One of the best things to focus on in this excellent short story is the way that Mansfield skillfully exposes the perception of Miss Brill as she regards her life and then the reality of her lonely, insignificant life that she almost manages to ignore, until the end of the story. Note that this is achieved through the point of view, which is stream-of-consciousness and follows the thoughts of Miss Brill as she sets off for her afternoon trip to the park and then returns home. Clearly, she is a character who deludes herself about her own significance and importance. Perhaps this is most clearly seen when she imagines that the park, and all the people there, including herself, are part of some dramatic play:

They were all on the stage. They weren't only the audience, not only looking on; they were acting. Even she had a part and came every Sunday. No doubt somebody would have noticed if she hadn't been there; she was part of the performance after all.

In Miss Brill's imagination, she is important and has a role, and her absence would be noted. The reality becomes crushingly clear at the end of the story when she returns to "her room like a cupboard" and lets out an involuntary sob. A good thesis statement would therefore be something like:

In "Miss Brill," Mansfield opposes appearances vs. reality to show the intense loneliness of the protagonist.

This thesis statement gives opportunity for the exploration of this theme and how Mansfield resolves the story.

A good thesis statement for any story is always a thesis that you feel strongly about and can find enough evidence to defend. It's possible that you don't care at all about the story. In that case, just come up with a thesis that is easily supported by the text.

You can go two ways with thesis statements.  

One way is the "point and counterpoint" thesis. This is my personal favorite, because it gives a lot to write about. Plus it has the advantage of allowing you to discuss and discredit arguments against your thesis. This kind of thesis is easily started with the word "although." I can't write out a thesis word for word for you about this story, but I can give an example of this thesis style: "Although Chocolat presents the viewer with many Christian characters, the only character who truly acts like a professing Christian is the outspoken atheist." For "Miss Brill," this kind of thesis would work well with the themes of appearance and reality. Miss Brill believes that she appears to be completely with it, when in reality she is just as much of an oddity as the people she critiques.  

The second way to go about forming a thesis statement is the "statement followed by reasons" thesis. This thesis style is much more straightforward. You say something bold, and then you tell your reader up to three reasons why that statement is correct. For example: "Chocolat represents strong anti-Christian biasing because it portrays Christians as hypocritical, ignorant, and stuck up." For "Miss Brill" and this kind of thesis, I would focus on the theme of loneliness and why Miss Brill is a very lonely character.

As a variation of that thesis statement, you might consider how Miss Brill compensates for her loneliness. The thesis would then be phrased something like:  The central theme of “Miss Brill” is the pain of loneliness, and inadvertent attempts lonely people make to experience life through the experiences of total strangers.  Some of your evidence that Miss Brill is starving for warmth and companionship would include that  she tenderly caresses her fur as if it were a beloved pet when she rubs “the life into the dim little eyes” of the old fox boa. Another sign of Miss Brill’s need for companionship is evident in her perception of the music which the band is playing at the Jardins Publiques: “It was like some one playing with only the family to listen.”  Good luck.  This is a wonderful short story to write about!

The answer to this is going to depend greatly on what the rest of your essay is about. Most essays, I argue, should look at themes and authorial purpose (why the text was written) so ending with a summary of these in relation to your topic is a good idea.

"Miss Brill" looks at lonliness and false perceptions. Miss Brill herself thinks that she is fashionable and looked upon with kindness. Her epiphany comes when she overhears a young couple talking about her and realises that she is just some faded old woman that no one cares about.

A lot of Mansfield's work looks at the themes of class and where one fits into the world and "Miss Brill" is no exception. The title is rather ironic as there is nothing brilliant or dazzling about this woman at all.

Looking at these ideas should give you a good in as to how you should be concluding your work.