When your opponent reaches third base, keep the joystick held left, hold down 'shift' and press fire and the player will be hit out every time.
Stand in the very top corner while batting and it is possible to hit the ball out of the stadium.
When the computer is pitching, press 'P' to go to the substitution screen where you can change the computers pitcher for an inferior one.
When your opponent reaches third base, hold the joystick left, hold down 'SHIFT' and press Fire, and he will be hit out.