A commentary essay, usually aimed at an academic audience, strives to help its audience make sense of a topic covered in another essay or article. Commentary essays are written critically and formally, with objective and subjective standpoints. Commentary essays are written independent of the essay they are covering but act as an extension of the original essay and topic.
Format your essay appropriately. The commentary essay should reference the essay you are writing about. Your commentary should be between four and six double-spaced pages plus a title page. Use a Times New Roman or similar font. Use MLA or APA guidelines if your essay is for a classroom assignment and you're instructed to do so.
Determine your audience. It's essential when you write a commentary essay that you write toward an audience that can relate to the topic your essay is about. If your topic is about controversial advances in medicine, your commentary will be slanted toward doctors and other professionals in the medical field, and your goal will be to provide a commentary that will encourage these professionals to view the subject in a way other than initially presented.
Write formally. The use of the personal pronoun "I" is acceptable when relating your personal viewpoint or stand on a subject, but avoid overusing it. Your personal stance on your topic should not overshadow, or act as, the basis of your commentary. Persuade your readers to look at the original topic from your perspective, don't force them to do it. This means you should keep a professional writing approach based on research and facts, not just personal opinion.
Structure your paper with an introduction, the original argument, your opposing argument and the facts that will support your argument. Summarise your viewpoint and ask your audience to consider the subject in the light you've presented it.
Include at least three sources for your article, cited as stated in the style guideline of your paper. One of the sources should be someone academic or who is in a field related to the object of your commentary. Source material might include trade journals, books or academic essays on the subject.