Everything in an essay then, must relate to the thesis, for the essay is about the thesis and nothing else. Another essential characteristic of an expository essay is that it is structured to explain and support the thesis. For this reason, it is to the writer's advantage, as well as the reader's, to formulate a thesis that will serve as a clear blueprint for an expository essay. The key to good exposition writing is revising. Often a writer must produce several drafts of an essay before the thesis become clear.
Many writers only discover their thesis statement in the final paragraph of the first draft.
Then they move that paragraph to the beginning and restructure the next draft around it. In any case, the more you revise the ideas and the language in an expository essay, the clearer and more polished they will become. The purpose of a reaction essay is to articulate your thoughts and impressions about some topic in a way that brings its significance into focus. One way to begin is with free writing. Write down quickly whatever you found memorable about the topic.