intelligence comes from not jumping to conclusions, but taking the time to analyze something and form a definitive answer; intelligence also comes from knowing when to do something, and when to let it go. people get smart not because they read books or literature, but because they observe life and draw their own conclusions.
Luck, and good gene's.
Oh, and curiosity, too. The smartest people I've ever known all had a child-like enthusiasm about their given subject.
It's more being able to blend common sense, street and book smarts.
being edumicated and eating vegetables. lol
Falling down the stairs? Youch that smarts!
perfect timing, homework and a pinch of luck.