CPU: Not possible, as it's locked, and you don't have/can't get aftermarket cooling for All-In Ones.
RAM: Probably not worth the trouble.
GPU: You can't do much with Intel HD Graphics of any kind.
So in summary, you really won't be getting anywhere trying to overclock ANYTHING in this system. As ThatVietGuy said, cooling would be an awful ordeal.
Sorry we couldn't help you further....