Comparison Paragraphs Organized by Similar Points

Consider the following paragraph:
 

The four dots [ . . . . ] at the end of this paragraph mean that the paragraph contains more sentences that are not shown here.)

The passage above is from a comparison paragraph. that is, a paragraph which discusses the similarities between two subtopics. Notice how the ideas in this paragraph are organized. As usual, the topic sentence is at the beginning of the paragraph. (For more about topic sentences, click here.) After that, the paragraph continues by discussing one point of similarity between the towns of Gridlock and Subnormal, namely, their small population. Specific details are given to support the statment that "both are small rural communities." (For more about supporting details, click here.) Following this, the paragraph briefly discusses a second point of similarity between the two towns, that is, their geographic surroundings. Here, the paragraph also gives supporting details to illustrate their similarity, namely, that they are "both located in rural areas."

As you can see, therefore, this comparison paragraph is structured (organized) according to the points of similarity between the two towns. This particular paragraph discusses only two points of similarity, but of course we can imagine a paragraph that gives three, four, or even more points of similarity. This paragraph, for example, might continue in this way:

(Note: The three dots [ . . . ] at the beginning of the above paragraph indicate that the paragraph contains previous sentences that are not shown here.)

We can place the points of similarity and their supporting details in a table in order to see more clearly how this short paragraph is organized:

Comparison Paragraphs Organized by Subtopic

Another way of organizing a comparison is not according to supporting details that are similar, but according to subtopic. (A subtopic is a main example, or main supporting idea, that illustrates the topic sentence of a paragraph. For more about supporting details, click here.) That is, we can organize the paragraph by first discussing all the relevant points associated to one subtopic, then discussing those of the second subtopic. Look at the following example, based on the above paragraph:
 

As you can see, after the topic sentence, this paragraph first discusses the relevant details about Gridlock and then presents the details about Subnormal. As with the paragraph above, we can illustrate this paragraph's structure in the following way:

Comparison Conjunctions

In the above paragraphs you will see various conjunctions that contribute to paragraph coherence. (For more on coherence, click here.) We can look at the above paragraphs again to see how the conjunctions are used:
 

This paragraph, of course, is organized according to similarities.   Notice how the ORDER of the similarities is the same throughout the paragraph. That is, at each similar point, the paragraph first discusses Gridlock and then it discusses Subnormal. Keeping the same order throughout the paragraph prevents the reader from getting confused.   Also notice how the conjunctions (for example, similarly, and ...X are similar in that...) are placed near each similar point.   Now examine the following paragraph, which is organized by subtopic:
 

These are not the only ways to give coherence to a comparison paragraph. There are other conjunctions, too. Here is a list of comparison conjunctions you can use:

Contrast Paragraphs

As mentioned above, a contrast paragraph discusses the differences between (at least) two things. You can organize contrast paragraphs in much the same way that you can organize comparison paragraphs. That is, you can organize them either according to points of similarity or according to subtopic. Here is an example of such a paragraph organized by subtopic. Notice the contrastive expressions in bold letters:
 

Here are some contrast conjunctions that you can use:

Source: http://lrs.ed.uiuc.edu