How to write topic sentences
Every paragraph in your paper needs a topic sentence. The topic sentence expresses what the paragraph is about. It should include two key things:
- The topic of the paragraph
- The central point of the paragraph.
After the topic sentence, you expand on the point with evidence and examples.
To build a well-structured argument, you can also use your topic sentences to transition smoothly between paragraphs and show the connections between your points.
Writing strong topic sentences
Topic sentences aren’t the first or the last thing you write – you’ll develop them throughout the writing process. To make sure every topic sentence and paragraph serves your argument, follow these steps.
Step 1: Write a thesis statement
The first step to developing your topic sentences is to make sure you have a strong thesis statement. The thesis statement sums up the purpose and argument of the whole paper.
Thesis statement example
Food is an increasingly urgent environmental issue, and to reduce humans’ impact on the planet, it is necessary to change global patterns of food production and consumption.
Step 2: Make an essay outline and draft topic sentences
Next, you should make an outline of your essay’s structure, planning what you want to say in each paragraph and what evidence you’ll use.
At this stage, you can draft a topic sentence that sums up the main point you want to make in each paragraph. The topic sentences should be more specific than the thesis statement, but always clearly related to it.
Topic sentence example
Research has consistently shown that the meat industry has a significant environmental impact.
Step 3: Expand with evidence
The rest of the paragraph should flow logically from the topic sentence, expanding on the point with evidence, examples, or argumentation. This helps keep your paragraphs focused: everything you write should relate to the central idea expressed in the topic sentence.
In our example, you might mention specific research studies and statistics that support your point about the overall impact of the meat industry.
Step 4: Refine your topic sentences
Topic sentences usually start out as simple statements. But it’s important to revise them as you write, making sure they match the content of each paragraph.
A good topic sentence is specific enough to give a clear sense of what to expect from the paragraph, but general enough that it doesn’t give everything away. You can think of it like a signpost: it should tell the reader which direction your argument is going in.
To make your writing stronger and ensure the connections between your paragraphs are clear and logical, you can also use topic sentences to create smooth transitions.
Topic sentences as transitions between paragraphs
As you write each paragraph, ask yourself: how does this point relate to what you wrote in the preceding paragraph? Depending on the answer, your topic sentence might do any of the following things.
Emphasize and expand
If the paragraph goes into more detail or gives another example to make the same point, the topic sentence can use words that imply emphasis or similarity (for example, furthermore, indeed, in fact, also).
Indeed, cattle farming alone is responsible for a large proportion of greenhouse gas emissions.
Summarize and anticipate
If the paragraph turns to a different aspect of the same subject, the topic sentence can briefly sum up the previous paragraph and anticipate the new information that will appear in this one.
While beef clearly has the most dramatic footprint, other animal products also have serious impacts in terms of emissions, water and land use.
Compare and contrast
If the paragraph makes a comparison or introduces contrasting information, the topic sentence can use words that highlight difference or conflict (for example, in contrast, however, yet, on the other hand).
However, the environmental costs of dietary choices are not always clear-cut; in some cases, small-scale livestock farming is more sustainable than plant-based food production.
You can also imply contrast or complicate your argument by formulating the topic sentence as a question.
Is veganism the only solution, or are there more sustainable ways of producing meat and dairy?
Topic sentences that introduce more than one paragraph
Sometimes you can use a topic sentence to introduce several paragraphs at once.
All of the examples above address the environmental impact of meat-eating versus veganism. Together, they make up one coherent part of a larger argument, so the first paragraph could use a topic sentence to introduce the whole section.
Where does the topic sentence go?
The topic sentence usually goes at the very start of a paragraph, but sometimes it can come later to indicate a change of direction in the paragraph’s argument.
Given this evidence of the meat industry’s impact on the planet, veganism seems like the only environmentally responsible option for consumers. However, the environmental costs of dietary choices are not always clear-cut; in some cases, small-scale livestock farming is more sustainable than plant-based food production.
In this example, the first sentence summarizes the main point that has been made so far. Then the topic sentence indicates that this paragraph will address evidence that complicates or contradicts that point.
In more advanced or creative forms of academic writing, you can play with the placement of topic sentences to build suspense and give your arguments more force. But if in doubt, to keep your paper clear and focused, the easiest method is to place the topic sentence at the start of the paragraph.