Fully upgrade the Supra GT and you can earn some easy skill points in two locations. The first is the airport, in the north area of the region. You can drag race from one end of the air strip to the other, then use a hard brake/drift/j-turn and return in the opposite direction, earning a bunch of points each time. From the airport, you can find the second area by traveling south until you reach a dry river bed. Here, it is easy to string jumps and drifts together for skill multipliers. Drive on and off ledges at full speed to earn a bunch of great perks.