Analytical and expository essays are used to reflect in some way on a specific topic. The topic can be most anything, from a particular event or person to a scientific theory or political ideology. Regardless of what the essay is about, most analytical or expository essays conform to a specific structure. They all have an introduction, a main body and a conclusion. The process of getting to this structure may be different for everybody, but a series of basic steps do apply.
Select your topic. Try to pick something manageable, that will fit within the space specifications of your essay.
Organize your ideas. You can do this in several different ways. For instance, some people will simply make a list of their ideas and select the ones they like. Other people who think more visually might make a tree of their ideas, beginning with the central topic and drawing “branches” to represent other ideas working from the central topic. Some people might engage in free-writing -- simply putting their ideas on paper with no worries for structure, simply to see where their ideas go.
Write a thesis statement. This is the single most important section of your essay. The thesis statement is essentially a sentence that explains what your central argument or idea is. You will use this idea to develop everything else in your essay. While thesis statements are usually only one sentence long, they can be longer if necessary, but the more direct your thesis, the better.
With your thesis statement in mind, pick three or four ideas from your list that you feel support this statement.
Write a topic sentence for each one of these ideas. These will be the topic sentences for each paragraph of your essay's main body.
Plot the body of your essay. This is where your formal structure comes into play. Take each of the topic sentences you wrote for the main body, and decide the order in which you wish to present them. This material will be between the introduction and the conclusion.
Write your introduction. The introduction must include your thesis statement as well as the topic sentences for each paragraph in the main body. You also want to capture the reader's interest, making certain that he or she will read your essay all the way through.
Write a paragraph for each of the topic sentences. Expand upon how this topic sentence supports your thesis and provide any information to back up your statements.
Write a concluding paragraph for your essay. The conclusion must restate the thesis, restate each of your arguments in support of the thesis, and generally bring the essay to an effective close. Word all of these differently than you did at the beginning and in the body. Also, be sure to never introduce any new material in the conclusion.