Remember when your Facebook friends posted Top Fives instead of Mafia Wars updates? One of the most popular was "Top 5 things I never leave home without." Okay, quick, name five things you never leave home without: but not for you, for your main character.
Any of those five things can be used in your plot. The house keys can be used to stab someone in the eye. The gold necklace can be hocked. The iPod can be used to shut out an ugly conversation.
Or maybe your main character carries something special, like Miranda in Rebecca Stead's WHEN YOU REACH ME carries a copy of A WRINKLE IN TIME. Remember the magic glacial water the main character in the movie The Waterboy always had with him? That ended up being important. I love that movie.
So feel free to plant something in the first chapter or two for your main character (or any important character) to never leave home without. After all, you don't walk around without your baggage. Everyone carries something. Even Neanderthals probably wouldn't leave the cave without their special rock and sharpened stick.
-- Kate, Miss Perfecting the Pages