Life becomes boring when there is repetition. Everyone needs a change. Similarly, repetition in writing also creates a disinterest among the reader.
There are different ways by which we can avoid repetition of words or phrases.
We may use the 'full' word instead of a personal or an impersonal pronoun. Use personal pronouns ('she', 'I', 'our', etc.) or impersonal pronouns ('it', 'this', 'their', etc.) to begin a sentence.
We may also use alternative phrases instead of repeating the same phrase. We may also change the order of clauses within a sentence to bring about variety and beauty. We may join phrases, clauses or even sentences to bring in some variety to our writings. Sometimes we can combine a number of the above techniques at the same time.
Use substitutes or omit some words, which have been used previously. One may use auxiliary verbs, former’ and ‘latter’, etc. in order to avoid repeating the same words within a sentence or paragraph. If a comparison contains more than two people or things, use "first" or "last”.
Look at the following example.
Jack and Jill went up the hill; the former fell down and broke his crown while the latter came tumbling down after him.