Learn Your Baby's Body Language

It could mean: She's trying to lure you into a game of peekaboo. Babies pick up on how that game works pretty quickly, and even 8- or 9-month-olds can initiate it themselves.

How to respond: Throw a thin blanket over your baby's head and see if she can pull it off -- to your enthusiastic cries of "peekaboo!" Once she gets the hang of it, hide under the blanket yourself; she'll try to pull it off your head.

Or it could mean: She's ready to hit the sack. Just like adults, babies rub their eyes when they're exhausted.

How to respond: If she's yawning or snuggling with a favorite lovey, of course, put her down for a nap. You might even shorten your normal wind-down routine, reading a shorter book, for instance, or skipping your rendition of "Twinkle, Twinkle, Little Star" so she can get right to sleep.