The first License Tests in Gran Turismo 5 on the PlayStation 3 to unlock are the National B License Tests. Once you've unlocked them (which can be done by simply purchasing a car) you can start playing the challenges. This video will show you how to get the gold trophy on the third one (B-3).
Fight the urge to shift into 4th heading into the corner and brake a bit late into the corner while turning.
Note * Played with a regular six-axis PS3 controller.