Ah I see. So you weren't exaggerating then? That was really your first time playing? Pretty good then, you took first a couple of times.
The basics:
Use Turbo until you're about to overheat.
Drive over a red arrow to completely cool your engine.
Lay off both turbo and the accelerator when you're in the air to cool your engine a bit.
Line your wheels up with the ground to land without reducing speed.
Land perfectly on the other side of a ramp for a "smooth landing" bonus.
Perform a wheelie just before going off a ramp to jump farther.
Hit opponents with your back wheel to wreck them.