Audrey Owen, the great editor who writes and blogs at Writer’s Helper, has the best explanation of the difference between the active and passive voices I’ve ever seen. It’s her tip #10
Although she’s also got a bit of a technical explanation, it’s her example I love:
Active - The boy hit the ball.
Passive - The ball was hit by the boy.
The active voice is so much stronger. As a reader I love it; as a writer I know I slip into the passive voice out of laziness or fatigue.
Take time to find your passive voice writing and change it to active voice. You and your readers will be glad you did.
Write well and often,
Image from http://www.sxc.hu