Bah, Man U supporter eh? :P Come on, we all know that Arsenal are the best!
Anyways, I don't have this game, so I wouldn't know all the controls, but I do have a tip that my friend told me.

Easy goals:
When you get the ball, try and get past the defenders by sprinting (tapping Triangle). When the goalie is going up to you, press X and the ball will bounce back off the goalie, allowing you to easily score a goal.

Good luck, and, try to chose a good team.