Instruct your students to get out a pencil (not a pen) so that they can take notes, ask questions and make comments about the piece of expository writing as you review it as a class.
Focus students' attention on the introduction. It should set the stage for the essay and capture your attention. Some writers make the mistake of jumping in too fast by not setting the stage by introducing the topic; others take too long to get to the point. An effective intro should pique your curiosity and stimulate your interest so that you want to continue reading the essay, not toss it aside in a fit of disinterest.
Isolate the thesis statement. It should express the point of the paper and summarize its main ideas. It should be comprehensive, give direction to the paper and be compelling, if not provocative. A thesis statement that reads: "People should watch what they eat and exercise if they want to lose weight" will register a ho-hum response because it fails to break new ground. That said, a daring thesis statement must deliver on what it promises by "finding" support, proof and evidence in the paragraphs that follow.
Review the supporting paragraphs. Ensure that they either provide support for, develop, clarify, illustrate or explain the thesis statement. For the most disciplined exercise, read the thesis statement and then each supporting paragraph in an alternating fashion to ensure that both components are cohesive and unified.
Evaluate the writer's use of transitions between paragraphs. The essay should flow easily from one paragraph to the next with connecting words and phrases.
Critique the conclusion. It should not restate the thesis, word for word, but rather summarize the essay and, ideally, point forward without raising a new issue that takes the essay in a completely new direction.
Take a measure of the writer's credibility. The writer should come across as reasonable, logical and sensible and wholly believable, even if you personally disagree with the statements he puts forth.
Assess the tone of the essay. The essay may be informative, humorous or sarcastic, Even an "angry" writer can get away with blowing off a little steam, as long as he doesn't offend his audience. Whatever the word you choose, the tone should be appealing, not off-putting.
Inspect the mechanics of the expository piece for punctuation, spelling and grammar. The essay should be flawless, for good writers are careful writers.
Critique the essay's "readability factor." It should be engaging and interesting, with appropriate word choices. As writing is an art form, the essay also should be creative; at the least, it ought to express original thoughts and ideas.
Take a full measure of the essay, considering all of these benchmarks. Often, analyzing a piece of writing comes down to answering one question: "Did the piece 'work'?'"