easier

Go to the Achievements page on Nitro Type, and check the requirements for earning each achievement. For example, the requirements for one of them may be something like “0/50 races”, which just means that in order to get that achievement, you have to complete 50 races. It’s really quite simple.
 
Other than that, there are no shortcuts or “hacks”. By just racing a lot and frequently using nitros, you’re sure to rack up a bunch of achievements. 🙂