Use the passive voice sparingly but artfully

Passive voice is effective when you want to disguise the actor (Mistakes were made is more persuasive than Our client made mistakes), when the actor is hard to describe (such as when describing the legislative history of a statute), when dealing in abstractions (as in All men are created equal), when discussing many actors (as in The legislation was signed) or when you don’t know the actor (as in The building was vandalized).

But most passive constructions are simply wordy and impotent. Imagine if the anti-drug campaign Just Say No had been written in passive voice, as No Should Just Be Said. Contract language requiring that Notice must be given is ambiguous. Who should give the notice? 

Search for by and of to weed out passive voice. Set Grammar check on your word-processing software to flag passive-voice constructions.