Tricking The Game
It's all about the nitros. Drift round corners wherever possible to earn them, and when you spot some on the course (they look a bit like big white milk bottles) make sure you grab 'em.
Then, use them to takedown your opponents. One or two nitros triggered at once will give you enough speed to catch them up, so you can nudge them off the road. However, if you have three nitros triggered at once, just touching them is enough to take them down.
Don't forget that spanner in the Car menu screen - kitting your car out with all available tuning parts is important.