From Wikipedia (link):
E-Prime (short for English-Prime, sometimes denoted E′) is a version of the English language that excludes all forms of the verb to be. E-Prime does not allow conjugations of to be (am, are, is, was, were, be, been, being), archaic forms (e.g. art, wast, wert), or contractions (’s, ’m, ’re).
Some scholars advocate using E-Prime as a device to clarify thinking and strengthen writing. For example, the sentence “the film was good” could translate into E-Prime as “I liked the film” or as “the film made me laugh”. The E-Prime versions communicate the speaker’s experience rather than judgment, making it harder for the writer or reader to confuse opinion with fact.
This exercise helped me strengthen this sentence, I think.