Start the first sentence with a broad topic that will be narrowed. It may present a concrete fact that leads toward the main idea and moves the reader from general to specific. The second sentence should further explain the opening sentence and can foreshadow one of the body paragraphs.
Third and subsequent sentences (with the exception of the thesis) should continue to move the reader from general to specific and transition smoothly into the thesis.
The thesis statement should normally be located at the end of the introduction, express the substantive issue (which is the main idea), and may provide hints as to support to be presented.
Every paragraph in the text should include a topic sentence, at least three adequately-developed support sentences with logical transition between them, a clincher sentence (mini-conclusions), that transitions to the paragraph that follows.
The first sentence should restate the thesis and move the reader from specific to general.
The second and subsequent sentences (with the exception of the last) should express definite conclusions, rather than simple summarizations, of each body paragraph, and move the reader from general from specific.
The last sentence should be the most general in the closing and bring the paper’s thesis full circle by relating back to the opening sentence of the introduction.
Note: The same organization (structure) can apply to a five section paper, a five volume series of books or a paper of any length. A paper of fifty paragraphs begins with an introductory paragraph and ends with a conclusion!