Write an expository, narrative, descriptive, compare and contrast or persuasive essay on urban sprawl. Because urban sprawl is a controversial topic---some approve it, some loath it---it is ideal to use an essay form that allows you to voice both sides of the subject. For instance, in a persuasive essay you can speak in your own voice, citing examples either from personal experience or through research that will sway the reader to side with or against sprawl. In an expository essay, you can explain the subject from all sides, using research and facts, without giving any explicit bias on the topic.
Interview supporters and protesters of urban sprawl. Research on the topic is extensive, but people have views on the topic that largely go unexpressed. Contact a few supporters of urban sprawl communities or sprawl in general. For example, big corporation CEOs may find benefits in urban sprawl because it allows contracting companies to take on major projects that are good for the economy. A wildlife conservation activist will likely give a look at the other side: Urban sprawl endangers wild species, like coyotes, that are normally free to roam in the forests but are then run over by cars or run out due to deforestation.
Devote a section of your essay to explaining one major problem of urban sprawl--long commutes. A 20- or 30-minute trip to the grocery store, or a child's school, costs hundreds of gas dollars per month and pollution. Without trying to condemn people who live in these communities, offer ways to deflect cost and hazards to the environment, such as local free trade grocery stores for the community so that families could walk there together to shop.
Discuss the history of sprawl. In a 2005 book by Robert Bruegmann "Sprawl: A Compact History," the author tours the suburban landscapes of yesteryear. He writes that sprawl has been a feature of city life since the earliest times. For example, he writes that rustic "villa suburbana" were common housing communities in ancient Rome. Mention the history of urban sprawl, keeping in mind the type of essay you are writing---persuasive, compare/contrast, descriptive---so that you do not stray from the topic or tone.