Study the five organizational patterns of expository writing: description, comparison, cause-and-effect, problem-and-solution, and sequence. Description occurs when the author describes the topic by its features, characteristics and gives examples. Comparison takes place when the author discusses how two or more items are different or alike. Cause-and-effect is when the author lists causes and the subsequent effects. Problem-and-solution calls for the author to list a problem and give potential solutions. Sequence occurs when the author lists events or topics in either chronological or numerical order.
Determine which pattern will work best for your writing, and write on your chosen topic. Follow your particular organizational pattern and use the cue words that coincide with each pattern. For example, the cue words for the cause-and-effect pattern are "because," "therefore," "as a result" "reasons why" and "if ... then." Review a list of each pattern's cue words on the Stanford University website (stanford.edu/~arnetha/expowrite/info.html).
Read your finished writing aloud. This will allow you to hear any inconsistencies, potential grammar errors as well as determine the quality of the writing itself. Quality writing should flow smoothly. Be sure your writing is useful to people who would otherwise have no prior knowledge of your topic.