There's a great corner of the Internet of mostly female academic bloggers who write about their lives. They've got a meme going about advice for young girls. They are passing down to a younger generation certain life lessons that they learned the hard way.
From time to time, I think about what advice I would give a hypothetical daughter. My wise words are usually along the lines of "Flaunt it while you've got it, because everything is going to sag soon." Please read Geeky Mom, Dr. Crazy and others for more mature commentary.