Raise as much as they'll call with AA, whether it be 10BB or 50BB. Try and get as much in there preflop when you know you're ahead. With AKs, try and put them on a hand. You're most likely beat becuase they're betting but try and see if you can accurately put them on some holdings. Eventually you'll know when person A bets so much from such a position based on such and such action leading to him, he's usually got this.

-'rilla