Blog post on Upper Elementary Snapshots about Finding Details and Writing Summaries. She uses a non-fiction text for this lesson. There are examples, anchor charts, and a product (someone else's) advertised. There is also a link to a free article. Focused on fourth grade.
This is a good way to help students see the main idea of a nonfiction piece. It also helps them summarize a story so they can use this paper to reference the work later without searching the entire document again. Finally, it is a good way to show them that all good work has main points that are supported by details.