Easy points
At the start of each level, do backflips until the bonus reaches 0.
In level 10, use all of your lives to do backflips.
Front flips give you as many points as back flips. They are sometimes a lot easier to pull off.
Gaining speed
When in the air from a jump and are about to hit the ground, try to land on the start of a hill's downslope. You will pick up more speed. You will then have lots of speed to go over another hill. You will sail across the screen and save time racing the track.
When you are going downhill in the long downhill, press [Up] + [Left]. When you cross a bump, keep doing the same thing. This will make your truck do backflips. By doing this, you will skip a lot of rough terrain, thus saving you time.
Getting over hills
Pace yourself by pressing [Back] to decrease your speed. There is no time limit. From time to time, return to get more points from flips.
If you keep falling backwards after attempting one of the vertical hills, try getting a good run up and holding [Left] to gain speed when going uphill. Then, hold [Right] at about one truck's length before the corner. If done correctly, you should go forward and make it over the hill.
When trying to go uphill, press [Up] + [Left]. This will give you a boost.