If we're just talking "different" and not "GT" then the first thing I actually noticed was that DS was super-super clingy. Like permanently attached. To me. For four years. I didn't know that all babies weren't like that... (LOL)
The first thing I should have noticed but didn't was that while he was attached, he was always ALWAYS completely engaged and interacting both with me and everyone else. Not that he was always happy with them (LOL) but he didn't miss a single thing including every mood change, subtle cue, tone of voice, etc. That's the thing I've noticed about other babies that has, so far, been very nearly diagnostic. I'm not saying that a not-so-engaged baby can't be GT, (triple negative! ha! LOL) but that a completely "there" baby has always proved to be smarter-than-the-average-bear by the time s/he gets to toddler or preschool age.
