Choose a singular focus
Each paragraph should have a clear, singular focus to it. If there is an overriding error students make in writing essays, it is shifting topics within the same paragraph, rather than continuing to develop the same idea they began with. A paragraph is a discrete unit of thought that expands one specific idea, not three or four. If you find yourself shifting gears to start a new topic, begin a new paragraph instead.
Someone once compared the beginning of a new paragraph to the changing angle of a wall. When the angle of the wall changes, a new wall begins. Let your paragraphs be like that wall: running straight along a certain angle, and beginning anew when the angle changes.
Begin with a topic sentence
Nothing will help you keep a tighter focus on your paragraphs than topic sentences. A topic sentence is generally the first sentence of the paragraph, and it describes the claim or point of the paragraph, thus orienting the reader to the purpose of the paragraph. When you use topic sentences, your reader will invariably find it easier to follow your thoughts and argument. As an example, look at the first sentences of each paragraph on this page. The entire paragraph is focused around the stated topic sentence. Additionally, headings are used to make it even clearer and easier to follow. If you’re writing a long research essay (10 + pages), you might consider using headings.
Develop the idea
Invariably students shift topics and lose focus within their paragraphs because they do not know how to adequately develop their ideas. They usually know the paragraph needs to be longer, but they don’t know how to expand their idea to fill that length. Indeed a paragraph should be at least half a page long, but usually no more than one page. How, then, if you don’t have enough to say, do you fill that paragraph length? Instead of broadening the focus, which will only be another form of topic shifting, try implementing these techniques for development:
* illustrate your idea with examples
* give an authoritative quotation
* anticipate and respond to counterarguments
* back your ideas with more evidence
* offer another perspective to the idea
* brainstorm more insights about the idea
* elaborate on causes/effects, definitions, comparison/contrasts