Parallelism is an aspect of grammar that connects to lists. It means “to group similar parts of speech together.” The easiest way to learn about it is just to see it in real sentences:
Before: I like to eat pizza, watch movies, and dancing.
After: I like to eat pizza, watch movies, and dance. (gerund becomes infinitive)
Before: John should write the report quickly, accurately, and with precision.
After: John should write the report quickly, accurately, and precisely. (adjective becomes adverb)
Before: Alice will research the problem, gather information, and solutions will be evaluated.
After: Alice will research the problem, gather information, and evaluate solutions. (active and passive verb forms made only active)
Before: James played his guitar, was dancing, and had done yoga before we came home.
After: James had done yoga, played his guitar, and danced before we came home.(several verb tenses combined)
The easy rule is this: be consistent with parts of speech in your list. If it is a list of nouns, use only noun forms. If only verbs, use the same tense. Looking for these patterns will help you write and speak more clearly.
In creative writing, you can use the forms of the words and also the sounds or the spelling to create interest and excitement.