HT Games
Instructions
Purchase your first car and enter some of the club-level races located in the Beginner Hall. If you played Gran Turismo 3 and still have the game file saved, you can transfer up to 100,000 credits to your account and start the game with a much nicer car.
Complete the first race in the Special Conditions Hall. Using the prize car from this race, complete the second race in the same hall. Sell this second prize and you'll be over 200,000 credits richer, which should be enough cash to build a collection of decent cars.
Win as many driving missions as you can before entering the more advanced races held in the Professional and Endurance Halls This will hone your skills behind the "wheel" and hopefully land you with one or more race cars you can use in the harder events.
Enter and win the Nurburgring 24 Hour Endurance race. As a prize, you'll get the coveted Formula Gran Turismo '04 race car, which you can use to make quick work of the street races in the Special Conditions Hall. In general, this is the most versatile car in the game and will perform well in nearly all of the races.
Purchase a Mercedes SLR McLaren and practice driving it around the Nurburgring. Driving Mission 34 features both of these and is arguably the hardest one to beat, so you'll need to be extremely familiar with both the layout of the track and the handling of the car in order to do so.
Achieve gold medal times on each of the license tests. For most gamers this will be the most odious and time-consuming part of trying to finish the game. It can be done, however, and really only requires that you repeat the tests until getting the gold.