Teach students to find the topic sentences of paragraphs. These represent the main ideas of the building blocks for the larger piece of writing. A topic sentence is typically the first sentence of a paragraph, but it can be the final sentence or, rarely, one from the middle. The topic relates to every other sentence, so give students a choice of three sentences from the paragraph to check for relation to all of the other sentences.
In a well-written piece, all of the paragraphs focus on the main idea. Provide students with main idea statements and two or more pieces of writing with multiple paragraphs. Have them match the main ideas to the correct essays, stories or articles.
Show example articles and stories clipped from magazines or newspapers with titles that express their main ideas. (Be sure, first, that the titles actually do reflect the main ideas, as editors sometimes write headlines in a hurry.) Provide students with an article or story and three or more similar titles, one of which correctly sums up the main idea of the piece. Remind students that each paragraph should have a clear connection to the main idea. Instruct them to find the common thread throughout the piece, then choose the correct title for the article or story.
Review the connection between paragraphs' topics and the main idea of the entire piece. Practice finding a common idea shared by all paragraphs and creating a sentence to express it as the main idea of the piece. Have students find the main ideas of each paragraph and express them in single sentences. Finally, instruct students to distill the sentences into one sentence that sums them all up. That final sentence should be the main idea of the story, article or essay.