Paragraph development begins with the formulation of the controlling idea. This idea directs the paragraph’s development. Often, the controlling idea of a paragraph will appear in the form of a topic sentence. In some cases, you may need more than one sentence to express a paragraph’s controlling idea.

Controlling idea and topic sentence — Despite the fact that piranhas are relatively harmless, many people continue to believe the pervasive myth that piranhas are dangerous to humans.

Step 2. Elaborate on the controlling idea
Paragraph development continues with an elaboration on the controlling idea, perhaps with an explanation, implication, or statement about significance. Our example offers a possible explanation for the pervasiveness of the myth.

Elaboration — This impression of piranhas is exacerbated by their mischaracterization in popular media.

Step 3. Give an example (or multiple examples)
Paragraph development progresses with an example (or more) that illustrates the claims made in the previous sentences.

Example — For example, the promotional poster for the 1978 horror film Piranha features an oversized piranha poised to bite the leg of an unsuspecting woman.

Step 4. Explain the example(s)
The next movement in paragraph development is an explanation of each example and its relevance to the topic sentence. The explanation should demonstrate the value of the example as evidence to support the major claim, or focus, in your paragraph.

Continue the pattern of giving examples and explaining them until all points/examples that the writer deems necessary have been made and explained. NONE of your examples should be left unexplained. You might be able to explain the relationship between the example and the topic sentence in the same sentence which introduced the example. More often, however, you will need to explain that relationship in a separate sentence.