I've taught gifted kids for ten years and this is pretty much what I've boiled it down to. Doesn't have to have all but a combination is key. Oh, and it all comes naturally.
  1. Begins reading at age 3
  2. Can beat anyone at chess by age 5
  3. Knows all 8 planets by first grade...and a couple moons
  4. Likes The Beatles, Stones and/or Green Day, in that order
  5. Is funnier than you
  6. Forgot...and Pink Floyd
  7. Tends to lead in everything but loves to work alone
  8. Horrible handvwriting
  9. Finds pretty much everything in school easy and/or boring
  10. Inventive, creative, artistic and see what happens when you buy them a guitar