This is the outline I use to get my freshmen writing high school-level essays. It's not self-explanatory, so it requires a bit of explaining, which fits nicely if you're doing guided writing in your class. It breaks down an essay into its most basic components...something my students have problems with. These components include the hook, arguments, and thesis (intro); body paragraphs with opening and closing lines; the conclusion; and a place for their citations.
I would be happy to answer any questions or send different copies of this handout, if need be. Just drop me a note via this site.