The parallel turn is the building block for the successful ski racer. A pure carve, (the tip and tail following exactly the same path) is generally the most desired form of turn, with the inside ski mimicking the path and movement of the outside ski.

GIANT SLALOM AS THE BASE EVENT
Giant Slalom has typically been considered the base event for Slalom, Downhill and Super G. Today's equipment makes this concept even more real. The modern application of shorter skis and bigger sidecuts in all disciplines require the skier to expertly apply principles developed in Giant Slalom skiing to all events.

ANGULATION
Angulation provides the skier with two benefits. First, it edges the ski. Edging the ski and applying pressure allows it to form its reverse camber. Secondly, angulation provides the skier with a means to resist centrifugal force and remain in balance while applying proper pressure to the ski(s). Angulation should be applied only to the extent necessary. Over angulation may apply too much edge angle and thereby cause the skier to be slower than wanted.
Angulation comes primarily from the ankle, knee and hip. Minor turns on flatter terrain can be accomplished with only ankle angulation. More demanding turns may require ankle and knee angulation. The most demanding turns will require ankle, knee, and hip angulation.
All turns should be effected with a progression of angulation that starts with ankle angulation and progresses to the knee and hip as needed.

PRESSURE DISTRIBUTION
Generally, it is desirable to start the pure carving action early in the turn. This will be possible only when the skier can establish "early pressure" with the dominant ski(s). Optimally the skier will extend the leg(s), to provide early contact with the snow and early pressure. The skilled skier will do this while maintaining sufficient ankle bend to provide enough tip pressure so as to lead the carving ski(s) into the turn.
Evenly edged and pressured skis will provide the least resistance and the most speed. On flatter terrain and less demanding turns the practiced skiers will equally edge and pressure both skis in a parallel fashion. Even though skiers will try to maximize this concept, on steeper terrain and more demanding turns it is important to be strongly balanced and committed to the outside ski so that it will carve cleanly and maintain the optimum line and momentum. 

by SvetSki