Read the chapter and make notes. A summary requires at least a fairly strong understanding of what has been addressed in the chapter and what it means. While reading, take down key words, phrases, and ideas in order -- whether chronological or thematic.
Begin your paragraph with a topic sentence. The topic sentence should summarize the thesis or main idea of the chapter. Get right to the point: what is the thrust of the message contained in the chapter?
Use the body of the paragraph -- about three to five sentences -- to note key evidence, arguments, or points. Depending on the number of key points that you wish to list, use a sentence or so for each. Include only the most salient points and omit details -- you only have several sentences to make your point.
Write a concluding sentence that summarizes the significance of the chapter. Your final sentence should be used to explain what is significant or notable about the chapter. Do not introduce new information from the text in this sentence, use it instead to add your own analysis about why the text matters.