You can score easy goals by crossing from the side and pressing B for a bicycle kick/header (90% success rate).

Swap sides and sabotage your opponent's line up. Take off the king-pins, put center backs up front, etc. Then, resume control of your original team again and continue playing.

To easily fake the goalie out on the opposite team, press Black. The goalie will dive to a ball that is not there. Then, make a left or a right and press Y. Do not press B or the ball will go in an unwanted place.

Move the Right Analog-stick slightly towards you then immediately press B. You will be able to score a beautiful goal from about 30 meters with some nice action.