Unlimited Star Power
In the mushrom cup drive in circles go around 5 times and then hit a mystery box.
Turbo Boost Hint
Whenever you are just about to go off a ramp, press the R button to jump, exactly
when you are at the edge of the ramp for a turbo boost. If you time it right, your
character will perform a trick midair and you will receive increased speed for a short time.