This achievement is not terribly difficult to get, first of all because you only need to get first in every event on hard and you don't need to do fan runs or fan demands, which makes it so much easier.
The races in blur are easy to win, even on hard, just choose the fastest car, which would be the ACS1 Coupe for D class, unless the track doesn't have many corners, if it's all straights use the Rat Rod. For C class use the 69 Camaro. For B class use the Viper ACR or the HHR (Race) if you find yourself getting wrecked a lot. For A class use Shannon's Astra Extreme.
For destruction races focus on hitting a car with every bolt if you can, also aim for the car in front because you may start a combo. Later on the destructions require mass amounts of points, doing combos (drift shots and long shots) are a must. In the later destruction events you will start encountering Blue vipers, when destroyed they emit a barge, always aim for these they can sometimes take out up to 3 other cars giving you massive points. Second aim for the red hummers, they give you the biggest time bonus and points. For D class destruction use either the ACS1 Coupe or the rat rod. For C class use Audi TTS Coupe. For B class use the Chevrolet HHR (Race). For A class use Shannon's Astra Extreme.
Now onto the checkpoints, these are by far the hardest to get 1st on hard. I suggest playing them all on medium before you attempt hard, and don't expect to get 5 lights on your first try either. For checkpoints always choose the car with the most grip and always go for all the stop watches. If you can get all the stop watches and not crash you will almost always get 5 lights. The most important thing is getting stop watches and not crashing, so don't worry about a nitro or slowing down. Riding the walls while using a nitro is much slower than breaking and taking the inside to get a stop watch. For D class checkpoints use the ACS1 Coupe. For C class use the Audi TTS Coupe. For B class use the Focus RS (race) except on offroad tracks use the nemesis. For A class use Shannon's Astra extreme. The hardest checkpoint race will be Mt. Haruna - Descent. As i said before you need to focus on collecting every single stopwatch. If you miss one you may as well restart the race, or continue for practice and you might get lucky. Save your nitro's for when you know that there is a straight with no jump. Nitroing off of a jump will not save you time. Always stay on the road as much as you can so as not to slow down.
The last part of this is beating all the one-on-one's. These are very easy compared to checkpoint races, for more information on each one-on-one go to each individual achievement for beating them. It is still the same requirements and are not that much more difficult, either wreck them (faster and easier to wreck them than it is to beat them) or beat them to the finish. Using bolts or shunts is the easiest to wreck them.