Annabeth would be an apple. Fairly plain, but sweet and a classic.

Her ability to just roll with information given to her. It's not that she can't be surprised or shocked, it's just that so long as what she's being told is true (which isn't always the case) she make very little fuss about it.

Annabeth's biggest fear is lightning. Her father was killed when lightning struck her home and caused the building to burn down, and things only got worse from there. 

Having things repeated or reminded to her as if she is going to forget or didn't hear it the first time. She [i]knows[/i] what you said, you don't need to keep telling her. Doing so actually makes her try so hard to remember that one thing that she forgets other stuff.