Nearly all writing you do in school will be to make or illustrate a point. Description may be written to convey sense impressions only. And narration may be written to tell a story only. However, you will often use description and narration, as well as expository writing, to make or illustrate a point.
Once you have discovered and collected information on your topic, you can decide what point you want to make. Your point, or main idea, is called a thesis. A thesis sentence controls all information you include in your composition in the same way that a topic sentence controls all information you include in a paragraph. For example, you observed that teenagers on television are unlike real teenagers. Therefore, you might write as your thesis sentence, “Teenagers on television are portrayed unrealistically.” Your composition would develop that thesis sentence.
Look back at the information you have on the topic Television teenagers and the real thing. Included in the list are I like color television better than black and white and Parents think I watch too much TV. Although both these items have to do with the general subject television, neither relates to the specific topic Television teenagers and the real thing, nor to the thesis that television portrays teenagers unrealistically. Because neither piece of information develops the topic, both should be removed from the list. The topic of your paper is a specific part of a general subject, and the thesis is the point you want to make about the topic. When you select information for your paper, be certain it relates to the specific topic and that it supports your thesis.