If you're losing a game, whilst playing simply press the appropriate key to start a two player game and the other team should freeze letting you win kind of easily.
When you concede a penalty push the joystick up and keep the button pressed down and your goalie will always save it.
During play press 'CTRL' and 'ESC' simultaneously to loose with 5-0.
Immediately after you score a goal, keep on tapping the 'R' key to flick to and from the replay. About 50% of the time it will credit you with another goal even though you have only scored one. Be warned though - sometimes the opposition gets a goal instead of an extra one for yourself.