Once you have decided what things to compare, keep the following in mind:
Basis of Comparison
In order for your essay to be a success, you need to have a basis of comparison about the things that you’re comparing. Do the things have enough in common for it to make sense to write about them in a compare and contrast essay? For example, it would make sense to compare in-person and online courses because the two have enough in common to justify discussing the similarities and differences of the two types of courses.
When you use the alternating method, you discuss one aspect of the first item and then immediately discuss the same aspect of the second item. You may discuss the amount of computer time required for an in person course and an online course. You may state that while you need to work on the computer for both courses, you would need to spend twice as much time on the computer for the online course.
When you use the block method, you discuss one subject and then discuss the next subject. Usually, you would write one paragraph discussing the first subject and then write a second paragraph discussing the second subject and so on. For example, you may decide to discuss the costs associated with taking an online course. You may emphasize that while a person is getting the same education, he or she is saving by not having to drive to the college. In the next paragraph, you may discuss the costs associated with an in person course: gas, parking permits, babysitting, etc.
Finally, when you combine the two, you’re writing a compare and contrast essay that follows the combination method. You may spend a couple of body paragraphs using the alternating method and then decide to switch to the block method for a deeper analysis of each of the subjects.