Persuasive writing of any length is designed to get the reader to agree with the main idea. A properly written paragraph begins with the topic sentence, which in a persuasive paragraph would be the main idea that the author wants to communicate. After the topic sentence, it is important to use evidence that is compelling in support of the main idea, as well as commentary explaining why the evidence is relevant. Wrapping the paragraph up with a compelling conclusion leaves the reader with something to consider.
Here is an example of a correctly structured persuasive paragraph:
"Steroids and other performance-enhancing devices have made a mockery of many of the achievements in professional baseball. When Barry Bonds broke the record for home runs in a season, many people focused more on the fact that his head had increased by a full hat size since the beginning of his baseball career and that his body looked significantly larger than it had when he began to play. Roger Clemens' amazing achievements as a major league pitcher were overshadowed by the fact that he took substances that were against the rules of the game in order to gain the physical tools to dominate batters. The tragic collapse of Alex Rodriguez's career came, by and large, from the fact that he for so long refused to acknowledge that he had used the substances to gain an advantage. The gifts of these three players were so great that they would likely have entered the Hall of Fame without cheating, but fans will never know."