Teaching students to write expository essays begins with a lesson on general and specific topics, a discussion of organizational strategies, and a group thesis activity.
Teaching students to write essays that explain is a breeze once students learn about the different expository genres. Before assigning that first essay, make sure that your students have a good understanding of how to define a topic in general and specific terms
General to Specific Class Activity:
In order to teach students how to organize writing around a thesis or main idea, first show students how to draw specific ideas from general topics. Begin by writing the word "movies" on the board. Ask students to name types of movies (examples: action, romance, horror, suspense, comedy). Write down all of the genres that students name them without editing.
Next, ask students to provide examples of each genres. List these examples under the name of each genre.
Comedy
Now list and briefly describe various types of expository writing.
Ideally, you should provide students with expository essay models. If your language arts textbook does not provide such examples, you might use the grade appropriate examples from The Write Source.
Finally, explain to students that a thesis is a one-sentence unifying idea that guides any expository essay. Help students to find thesis examples in the essay examples you have provided.
Once you are certain that students understand the organizational writing models for expository essays, you are ready to practice with expository paragraphs. Resist the temptation to have students write full-length essays until you are certain that students have a handle on how to write single effective paragraph.