Do Wheelies!

Hit the throttle till you are going 100 mph on a straightaway, let go of the gas for a few seconds and then accelerate again.
Submitted by codeman10 

Tips/Hints

Tail Break

Learn to use the tailbreak for the best cornering. Using the tail break on tighter turns (turn while applying breakes) will allow you to enter the turn at a higher speed and corner tigher instead of slowing which lowers your turning radius

Muddy Tires

If your wheels go off the track, look at the damage indictor. If your wheels are red, then your wheels have picked up some mud. You'll have to take the next few corners cautiously until it wears off. 

Watch Mr Trainer

This might seem pointless, but you'll learn the best possible approach for corners which could help quite a bit in the long run.