Writing Good Paragraphs


The 8-sentence paragraph structure that you learn in composition class is a useful tool. But once you understand what the essential function of each paragraph element is, there is no need to stick to 8 sentences. Good paragraphs, after all, can be 15 or 20 sentences. They can also be 2 or 4. This handout explains the elements of a paragraph for an argumentative essay and explains what each of the following elements is supposed to do:


The Topic Sentence

On the most basic level, the topic sentence gives your reader some hint as to what this paragraph is about, but more broadly, the topic sentence is a smaller claim that points back to your main claim or thesis. It supports your thesis while advancing a contestable argument on its own, and like your main thesis, it should be supported with reasons that answer the question “why?”

“Carrots are an excellent healthy snack option because of X, Y, and Z.” (For, say, a hypothetical paper about the dietary needs of school children.)



Your evidence is essentially that X, Y, and Z. It tells us “why.” Evidence can consist of:

  • Direct citations or summaries of an outside source.
  • Details from an artifact (text, film, work of art) that you are analyzing.

It might go without saying, but all evidence presented in that particular paragraph should support the topic sentence or mini-thesis of that paragraph, not some other topic sentence.  If this paragraph in your nutrition paper is about carrots, don’t bring up blueberries.  Blueberries are another paragraph entirely.  Right now, you’ve asked your reader to concentrate on carrots, so don’t pull a bait and switch by shifting focus on them.



Your commentary is where you spell out how your evidence supports your topic sentence and ultimately the main thesis of your paper.  These are generally the most difficult sentences to write and are often neglected by student writers.  Most fear repeating themselves and feel that because they know how that evidence supports their thesis, everyone will be able to figure it out.  Here’s the thing though, your readers don’t have access to the specialized body of knowledge that qualified you to write this paper in the first place.  They are counting on you to educate them. 

Here is a paragraph without commentary:

“Carrots are an excellent healthy snack option because they contain beta carotene and Vitamin A, and they are delicious.  Studies show that carrots are the best source of beta carotene and Vitamin A among all vegetables.  They also contain moderate amounts of sugar, which makes them tastier than many other vegetables.”

Perhaps your reader hasn’t taken a nutrition class in a long time and has no idea what beta carotene and Vitamin A are or why they matter. And perhaps your reader will scoff at the claim that carrots are more delicious. Pizza is even more delicious.

Commentary is where you persuade your reader to care about the evidence you are offering.  Even though hard data is important, commentary is where the bulk of persuasion actually occurs.  So here’s that paragraph with some commentary thrown in:

“Carrots are an excellent healthy snack option because they contain beta carotene and Vitamin A, and they are delicious.  Study X demonstrates that carrots are the best source of beta carotene and Vitamin A among all vegetables (citation).  Both nutrients are needed by the retina in order to process light.  The molecule formed by Vitamin A aids the eye in seeing colors and seeing in low light conditions; therefore, carrots are one of the best foods one can eat in order to keep the eyes healthy (citation).  Carrots also contain moderate amounts of sugar, which makes them tastier than many other vegetables.  For that reason, raw baby carrots are an ideal snack food for both kids and adults.  Even when served with salad dressing or dips, carrots make for a tasty and much healthier snack than packaged foods high in processed sugars.”

Good commentary can even sneak in some additional evidence that helps explain why the major bit of evidence matters (such as the metabolic function of Vitamin A). 



Don’t try to force yourself to write a concluding sentence, especially if it’s of the “and that’s my carrot paragraph” hand-waving variety.  What you should really be concerned about is how you transition into the next paragraph.  Since I ended my carrot paragraph by talking about why they are an ideal snack, I might approach the next paragraph in a variety of ways:

  • Talk about another good snack food.
  • Talk about unhealthy snack foods and why they are bad.
  • Elaborate on how to create enticing but healthy snack options for children
  • Etc… (I’m sure you’re noticing the theme here).

Arranging paragraphs in this fashion gives the reader a sense that your major thesis is being fluidly developed.  The reader can chart your logic without feeling like the piece is jumping from one topic to another without any sense of connection.  Good argumentative papers have a telescoping quality (Paragraph 2 builds on the info offered in Paragraph 1, and the implications of both are considered in Paragraph 3, which takes us to Paragraph 4 where we talk about solutions to the problems raised in Paragraph 3, etc.). Weak papers have an additive quality (Thing 1 + Thing 2 + Thing 3 + etc.)



No matter how long your paragraph winds up being, no matter how many pieces of evidence are offered in it (it might only be one) or what the ratio of hard evidence to commentary is, the key here is coherence. The elements of your paragraph should work together to advance a subclaim that supports the main argument of your paper. You should present carefully chosen evidence that is relevant to that subclaim and explain what it means to your reader. And finally, you paragraph needs to have some identifiable relationship to the paragraphs around it. Once you have grasped those basic principles, you can adapt them to paragraphs of almost any length and level of complexity.

Download Handout