Once your baby starts hurling her sippy cup from the high chair -- between 10 and 12 months -- you'll want to begin saying "no" to her, firmly. But be prepared: It's a new word, so it'll take a while before she gets clued in to what it means. In the meantime, when your baby hears "no" and ...

...Stares blankly,
Try: Modeling better behavior. If your baby whacks the dog, pet it gently, and smile and say "Yes, that's good" when she mimics you.

...Bursts into tears,
Try: Softening your delivery next time. A loud voice or a stern expression can be frightening and teaches a child that only a loud voice is worth paying attention to. Just don't rush in to cuddle her to make her feel better or you'll send a mixed message.

... Giggles,
Try: Keeping a straight face. If you laugh along, you'll just encourage the mischief. Instead, repeat "no" firmly, then lavish her with smiles when she listens.

...Heads straight for the high-priced electronics,
Try: Offering a do instead of a don't. For example, try saying "Give me the remote" instead of "Don't chew on the remote." Better yet, keep breakables out of reach so you won't have to say no quite as often.