3. Another Character Reveals The Back Story – Have another character reveal the back story instead of your hero revealing his own. It never comes out right when the hero does it so having someone else revealing it can amplify a back story.
For example in the limo scene for Die Hard; the audience is dying to know the reason John is in to LA to visit his wife. Instead of John letting the driver know, especially since it goes against his character, the limo driver attempts to guess.
He guessed that she had left to pursue a bigger job. He guessed that John thought she would fail and move back to New York. John doesn’t say anything about his life but we still a lot of his back story.