Check for awkwardly repeated words. Sometimes repetition works well particularly to unify a paragraph with a series of parallel phrases or clauses or to repeat a term for emphasis. But repetition can sound monotonous when writer uses the same term too often or even in various forms. For instance, “They know that their knowledge is outmoded,” or “Their performance featured a variety of dances and various instrumental solos”. Such constructions look clumsy and are easily fixed. For example, you could write “They realize their knowledge is outmoded” or “Their performance featured a variety of dances and solos with different instruments.”