Because expository writing relies so heavily on clarity, extensive pre-writing is crucial when organizing the essay. Brainstorm your subject and write out lists of all main points and their relevant supporting details. Indicate which points are most important and rank them accordingly, so you can lead and finish with your strongest details. Furthermore, notice which points will provide smooth transitions to others, so you can begin to see the best and most logical organization for your material.
Determining the Best Structure
Once you've organized your material, you need to determine the appropriate structure for your essay. The New York Times Learning Network suggests abandoning the typical five-paragraph academic structure for a more "authentic" essay structure -- perhaps one that opens the essay with the most important points or a narrative that illustrates what you are discussing, allowing the theme to dictate the flow. This style of writing accommodates many styles of exposition, including description, anecdote, sequence, comparison, and cause and effect.
Incorporating Supporting Material
How you include supporting material affects how interesting the essay is to read. For example, if you cite all of your material in the same manner (i.e., MLA-style parenthetical citations), the essay might appear monotonous, despite the richness of the content. Try using quotes and attributing sources with signal phrases in addition to using parenthetical or footnote citations. For example, instead of citing the The New York Times via footnote, signal it in the beginning of a sentence: "According to The New York Times...," and then follow with a direct quote.
Create Sound Sentences
While pre-writing and organization are essential to a successful essay, precision with language is just as important. Make sure you state your ideas in the clearest ways possible. Use simple sentences whenever you can. Avoid obscure words when possible. Try to use parallel structure in your sentences and make sure you maintain subject-verb and noun-pronoun agreement throughout. Do your best to write sound sentences when drafting, but really focus on polishing them when editing and revising.