It's something I see all the time as a journalism professor - student-written news stories filled with sentences like these:
The bill was signed by the governor.
The ball was caught by the shortstop.
The budget was cut by the city council.
The side of beef was cut by the butcher.
The story was written by the newspaper reporter.
What's wrong with these sentences? They're not horrible, but they are written using a passive construction as opposed to an active construction we call subject-verb-object.
Subject-verb-object, or SVO for short, simply means putting the subject at the start of the sentence whenever possible. Using this formula the subject comes first, then the verb, then the object. What do I mean by this? Take a look at these two sentences:
The waitress read the book.
The book was read by the waitress.
What's the difference? The first sentence uses the active SVO construction, while the second one is passive. The first sentence has a very direct connection between the subject - the waitress - and the action she is taking - reading the book. That makes the sentence punchy and vivid. Indeed, as you read that sentence you can almost visualize a waitress poring over a book. Maybe she's on her break, sitting in the back of a grimy, noisy kitchen at a diner somewhere. But I digress.
The second sentence, on the other hand, severs the connection between the subject and the action she is taking. The result is a sentence that's dull and lifeless, one that doesn't conjure any images in the reader's mind.
There's another difference here: The first sentence is four words long, the second is six words long. That may not seem like a lot, but if you're writing, say, a 12-column inch news story and you can cut two or three words out of every sentence, that starts to add up. The end result is that when you use the SVO format, you can communicate a lot more information in a smaller space, what journalists call "writing tight." That's what newswriting is all about.
The great thing about the SVO format is that it's very easy to master. All you do is put the subject of your sentence at the start of the sentence. Try it with these examples:
The house was destroyed by the tornado.
The governor was angered by the legislature's actions.
The bill was vetoed by the president.
The police officer was cornered by the mob.
The escaped convict was hunted down by the townspeople.
The newspaper was shut down by the publisher.
The carnival was enjoyed by the children.
The amendment was rejected by the lawmakers.
That movie was ridiculed by my favorite critic.
The pass was caught by the team's star wide receiver.
Writing using an active construction would seem to be an easy enough thing to do, but even experienced reporters sometimes lapse into passive sentences. But if you get into the habit of writing in the active voice right from the very start, it will become second nature.
By the way, if you're still not sure how to do this, take a look at the sentences below. They're the same ones from above, just rewritten in the active voice.
The tornado destroyed the house.
The legislature's actions angered the governor.
The president vetoed the bill.
The mob cornered the police officer.
The townspeople hunted down the escaped convict.
The publisher shut down the newspaper.
The children enjoyed the carnival.
The lawmakers rejected the amendment.
My favorite critic ridiculed that movie.
The team's star wide receiver caught the pass.
You can find more subject verb object exercises here.