User can set up a Web cam pointed at the keyboard, on the desk or attaching a bracket to the keyboard.
When motion is detected on the Web cam feed a window pops up on the bottom of your field of view to help you finish placing your hands.
Size of the window and how long it should stay up should be customizable (touch typist might let it dissappear while hunt and pecked might want it up and fairly large a lot of the time)
Note that you don't have to be looking at the keyboard for this to work. The window pops up and helps you type regardless of where they keyboard is.