What are some ideas for an effective introduction to an essay which discusses why each character in The Glass Menagerie, by Tennessee Williams, clings to deceptions/illusions in order to survive harsh reality?
You have chosen to write your essay about a very interesting aspect of the characters in Tennessee Williams's The Glass Menagerie. I assume you will be writing about all four of the characters in the play, since all four of them believe in something other than reality in order to survive each day.
The introduction to any written work (or a speech) has two specific goals: it must capture the reader's interest and prepare the reader for what is to come. Several possibilities for capturing the reader’s interest include using an applicable quote from the literature or from something else (although it must be directly applicable to the literature), making a startling statement, telling a story, or giving an example to make a point. Each of these must connect directly to your body paragraphs or the reader will feel cheated or frustrated by the detour. A quote from the play would work, of course, but perhaps something from another source would be more effective:
Reality is merely an illusion, albeit a very persistent one. ~Albert Einstein
To prepare your readers for what is to come, every essay must have a statement of purpose (thesis statement) which previews the body points of the essay. This one sentence should be able to be removed from the essay and still clearly tell the reader what your essay is going to cover. In this case, perhaps something like this would work: Each of the characters in Tennessee Williams’s play The Glass Menagerie is living some kind of a lie; they do so in order to avoid the often harsh realities of their lives. This would be followed by four body paragraphs discussing each of the four characters and their “deceptions/illusions.”
An introduction is integral to a successful essay—and do not neglect an effective title, which is the very first impression your readers have about your essay.