Call of Duty: Modern Warfare 2/Race

Strategy
Press drive 0.5 seconds after the word GO! appears; this gives you a "Quick Start" boost at the beginning (this also works for Time Trial). You can shoot enemies but it is inadvisable to do so.

Keep to the right at the beginning, but stay left of the rocks that are on the ground. To increase control of turns, release the gas while turning. Do not ramp off the hill; go around the left side. Keep near the right and enter the narrow passage. When you reach the fork going left and right, take the left fork. Fly off the hill into the open area. At this point, you must be at 0:34 or less to get 3 stars.

Drive into the open area, and aim at the right side of the hill ahead; do not drive over it. Drive into the passage ahead and make a sharp turn right toward the top of the slope. At the top, you must be at 0:54 or less to get 3 stars.

Go down the slope, carefully avoiding the trees. If you made it to the bottom, ramp off the slope to the finish line.

Alternate Shortcut
Near the beginning, before heading into the first narrow passage, you can save about 2 seconds by cutting through the trees. However, it is very risky.