When you are in a season/Career, when you get close to the ball, stand near it for two or more seconds, then you should be able to kick the ball much harder and futher; this will improve your game.
(Hold the X button to get a more desired kick)
Pick someone on your team to get the ball, and go to one of the four corners. When your opponent comes and tries to steal the ball from you, position yourself so they have to slidetackle you. They should get a yellow card. Continue untill the oppossing team has had enough red cards so they have to forfeit.
When the opposition goalie has the ball in his hands at the left or right edge of the box, you slide tackle him. You will get a red card but when the goalie takes the free kick he will be at the edge of the box. When he takes it you immmediately power-up 2 shoot(not 2 much or it will go wide or over the goals) you will score because the goalie was too wide.
To unlock each team you must win the World Cup with a team from a certain regions:
All-Europe Team: Europe Region
All-Americas Team: N. or S. America Region
All-Africa Team: Africa Region
All-Asia Team: Asia Region
All-World Team: All regions