To use parallelism in writing, you should ensure the structure of the sentence or sentences is such that meaning remains clear and that you do not commit stylistic errors. This means that you should be sure to set up a single subject properly for parallel structure, or to state new objects or subjects for each clause in a sentence if needed. You should also be sure to use proper subjects and parallel structures that do not become confusing, by comparing two things that do not make sense. If you are using parallelism in writing between multiple sentences, then you should structure each of them similarly to ensure readers pick up on the parallel.
Parallelism in writing can be used in a number of different ways for a variety of reasons, though you might typically use it to make sentences flow more smoothly. For example, you could write out a sentence like “The man was short, he had a poor complexion, his feet were too large, and he always wore dark clothes.” The repetition of the subject in each clause of the sentence, however, becomes excessive and unpleasant to read. While repetition is not inherently detrimental, it can become tiresome in some instances.
When you are using parallelism in writing, you can make this type of sentence flow better through rewriting it as, “The short man has a poor complexion, large feet, and a penchant for dark clothing.” Proper parallelism allows each following clause to function off of the verb or predicate used in the initial clause. In this example, the word “has” in the first clause applies to each one that follows it. Improper structure, which you should avoid, would be a statement like, “The man is short, has large feet, and prefers to wear dark clothing.” While this is not grammatically incorrect, the need for a verb in each clause that follows inhibits the effectiveness of the parallel.
If you are using parallelism in writing between two or more clauses, to create a comparison or connection between two ideas, then you should be sure to structure them in a way that creates a clear parallel. Two phrases like “The dog was happy,” and “The clouds were fluffy,” could be considered parallels but the connection is rather vague. A more pronounced parallel between these ideas could be constructed as, “Happiness is the natural order of dogs, as fluffiness is the natural order of clouds.” This demonstrates a much more pronounced sort of parallel through the repetition of key words, and while such repetition is not required, it can make two phrases connect and stand out more strongly within a text.
You should be careful when using parallelism in writing in this way, however, to ensure that a connection makes sense. A statement like, “My house, my paycheck, and my family are large” has some inherent logical problems. The size of the house is measured in terms of spatial capacity, while a paycheck is measured in terms of numerical quantity, and a family is measured with regard to the number of people within it. While this type of sentence can be used for irony or comedy, to compare dissimilar things along seemingly identical terms, you should avoid unnecessary confusion when using parallelism.