The trick to effective blocking is learning when to use the different blocks. Impact Blocks (Right Analog-stick Up) are more effective if you have a size advantage against the player you are blocking, while Cut Blocks (Right Analog-stick Down) are more effective if the defender is bigger than you. Turn Blocking (White and Black) works best for offensive linemen when they are trying to create an interior hole for the running back. If you get beat and you must resort to dirty tactics, try Holding (L).