New to football

I am really starting to like American football now... I dont know much about the rules though. So I decided to get the madden football game for the play station at the moment I am not very good playing it... I cannot seem to get any interceptions complete my players every single time just seem to want to drop the ball when they get it which really is not good at all even though I do what the manual tells me to do and press triangle but every single time I fail... I dont think I have been able to make a successful interception thus far. But I gotta say that the games I do play I always seem to win even though my defense is super weak my offense on the other hand is super strong though! I find picking up the rules is a lot easier when you are actually playing it for yourself.. unfortunately I do not live in America so non of my friends will play it with me though which is a shame because it is so much better than European football I think.