As you start planning your paper, be prepared to cover both subjects in a similar fashion. Return to your table or make a scratch outline so that you can refine your points of comparison or contrast, consolidate supporting details, and spot gaps in your information. Remind yourself of your goal. What is it you want to show, argue, or find out?

State Your Purpose in a Thesis. You need a reason to place two subjects side by side — a reason that you and your audience will find compelling and worthwhile. If you prefer one subject over the other, what reasons can you give for your preference? If you don’t have a preference, try instead to understand them more clearly, making a point about each or both. Comparing and contrasting need not be a meaningless exercise. Instead, think clearly and pointedly in order to explain an idea you care about.

Select a Pattern to Help Your Audience. Besides understanding your purpose and thesis, readers also need to follow your supporting evidence — the clusters of details that reveal the nature of each subject you consider. They’re likely to expect you to follow one of two ways to organize a comparison-and-contrast essay. Both patterns present the same information, but each has its own advantages and disadvantages.

Use the Opposing Pattern of Organization. When you use the opposing pattern of subject by subject, you state all your observations about subject A and then do the same for subject B. In the following paragraph from Whole-Brain Thinking (New York: William Morrow, 1984), Jacquelyn Wonder and Priscilla Donovan use the opposing pattern of organization to explain the differences in the brains of females and males.

At birth there are basic differences between male and female brains. The female cortex is more fully developed. The sound of the human voice elicits more left-brain activity in infant girls than in infant boys, accounting in part for the earlier development in females of language. Baby girls have larger connectors between the brain’s hemispheres and thus integrate information more skillfully. This flexibility bestows greater verbal and intuitive skills. Male infants lack this ready communication between the brain’s lobes; therefore, messages are routed and rerouted to the right brain, producing larger right hemispheres. The size advantage accounts for males having greater spatial and physical abilities and explains why they may become more highly lateralized and skilled in specific areas.

For a single paragraph or a short essay, the opposing pattern can effectively unify all the details about each subject. For a long essay or a complicated subject, it has a drawback: readers might find it difficult to remember all the separate information about subject A while reading about subject B.

Use the Alternating Pattern of Organization. There’s a better way to organize most long papers: the alternating pattern of point by point. Using this method you take up one point at a time, applying it first to one subject and then to the other. Jacob Griffin uses this pattern to lead the reader along clearly and carefully, looking at each subject before moving on to the next point.

I. Similarities of styles

A. American popularity through movies

B. Variety within styles

C. Emphasis on internal values

II. Differences between styles

A. Age and origins

B. Techniques

C. Uniforms and weapons

Add Transitions. Once your essay is organized, you can bring cohesion to it through effective transitional words and phrases — on the other hand, in contrast, also, both, yet, although, finally, unlike. Your choice of wording will depend on the content, but keep it varied and smooth. Jarring, choppy transitions distract attention instead of contributing to a unified essay, each part working to support a meaningful thesis.