Forza Horizon 2 Presents Fast Furious

All of the "skill" achievements are incredibly easy and you shouldn't even have to try for most of them. While 100,000 points may seem daunting, just don't worry about it and play through the game going for other achievements. It will come naturally and surprisingly quickly if you're actively completing story missions and going for other skill achievements.

You'll know when you have performed one of the "skills" because it will display a little score near the top of the screen for it and say which skill it is ("Good [skill]!"). But again, don't bother worrying about how many you have left. It should pop about halfway through the game.