Test Drive Unlimited

The race challenges are the ones with the checkered flag icon. Some of them are point-to-point and some are several laps around a circuit. In all races you'll have several opponents and you'll start in last place. Some races will be limited to certain car/bike classes or makes of cars. You will usually race against a variety of opponents that meet the race's requirements of make and class but usually only one or two will be viable contenders. The other racers will be wildly outclassed and are just obstacles in the first few seconds of the race.

NOTE: Due to the way the game is structured, you really can't just go after all the races and ignore everything else. You'll be making progress towards this achievement throughout the game in parallel with the other event achievements.

First of all, you'll need to find all the races. Get a map (link below) and drive around the island until you've discovered them all. You might as well do this early on since you'll want to find all the dealerships and tuning shops as well. You won't get to see some of the races until you are at higher level but if you've driven past that spot on the map they will show up as you level.

Next, you'll need some cash to buy cars and tune them. You'll need at least one good car and bike from each class plus a few extra cars for the make-specific races like Pagani Day. In each class there are a few cars which are clearly better than the others. You'll find many opinions online but here's a brief list:

G: Lamborghini Miura*
F: Audi TT
E: Nissan Skyline
D: Aston Martin DB9
C: Ferrari 575M Maranello
B: Ferrari F430 coupe
A: Enzo Ferrari

* In any racing game where there is an "old cars" class you'll usually want the Miura. It's very fast and easily out-handles the muscle cars due to its low center of gravity.

Each car should be tuned as high as you can without changing the car's class. For most cars this will be level 3 though there are a few cars (like the Alfa GT 3.2 V6) that will change class if you tune them too high. When you tune cars, go right to the highest level you want. If you, say, tune a level 1 car to level 3, you do NOT get a refund on the level 1 cost. Tuning to anything less than the highest level you want is a waste of money.

If you need money to buy cars, there are two easy ways to earn it. One is to do the courier and car delivery races, which pay very well and are easy. The second is to find a well-paying event that you can do quickly. The best of these is the 180 mph in traffic event near the center of the island but that is not unlocked until later in the game. When you unlock that event, you can turn the car around for a nice straight shot to 180 mph and $70k in about a minute with level 3 Saleen S7. There is a similar race that is unlocked very early in the game in the SE corner of the island and the same trick works there (turn around for a nice straight shot to the target speed and $$$).

When it comes to the races, if you have a good car at tuning level 3 you will easily out-car all your opponents so, even if you are not good at racing games you will often win even the hardest races. The key part of any race is the beginning where you want to make sure you power into the lead within the first 30 seconds. Once you've got the lead it's pretty easy to hold it - just make sure you slow down for turns and watch out for traffic. If you don't remember to brake for turns you'll overshoot them or ram the barricade and allow your opponents to catch up. As for traffic, try to keep to the breakdown lanes on the side of the road and watch for cars entering or leaving the road. It's usually better to slow down to avoid a crash than to lose your lead to a collision. One other trick to try is, when the computer is neck-and-neck with you or is passing you, nudging them over into an obstacle, like if you were playing Burnout. It doesn't always work, but it's a nice way to take out one of your main opponents if it does.

The race events are, in my opinion, the easiest ones in the game since you only have to suck less than your opponents and you can easily out-car and out-tune the opposition.

You can find a lot of information on the web about TDU but this is probably the best site I've seen for it:

http://guides.gamepressure.com/testdriveunlimited/