An essay paragraph is a series of sentences that are all about the same concept. Each paragraph is about a different concept, but all concepts support the thesis, the argument or idea presented in the introduction. Paragraphs can present one or both sides of an argument. The paragraph with the strongest supporting argument for the thesis should be your first or last paragraph. Traditional essays have three paragraphs, but that's not a hard and fast rule: Some essay bodies have only one paragraph while others have more than 20.
Each body paragraph has a topic sentence. Typically the first sentence, this presents the main idea and introduces the content of the paragraph. Focus your topic sentence so it doesn't wander off into tangential territory.
The evidence is the information that fills in the rest of the paragraph after the topic sentence. Evidence includes facts, details, examples and interpretations that support the assertion made in the topic sentence. Evidence can be culled from a range of sources, including interviews, other writings, scientific experiments, polls, historical events and your own experiences. Evidence might even come from your own imagination if that is appropriate to your topic.
The last sentence of each body paragraph can be a transitional sentence. The transitional sentence closes the paragraph with a concluding point and prepares the reader for the concept put forth in the next paragraph.