The old joke about the ski instructor who can only say, "Bend zee knees. Two dollars please!" still persists. For decades instructors believed control came from driving the knees forward to push the shins into the boot tongues (1). Then, to get the skis on edge, skiers had to crank the knees sideways to tilt the lower leg bones (1-2). To complete the turn they kept forcing the knees ahead to maintain leverage on the forebodies of the skis (3). This still works fine, especially where it's steep and you need to make short turns to control speed. But shaped skis don't necessarily like to be treated this way.
A Softer Touch
Modern skis like their rider to exert power, but they don't want it applied harshly. They also get nervous when you try to stand too far forward. By letting your hips stay inside while your feet flow out from under you (A), you can gain a high edge and be in a strong position to start a turn. Your knees should stay slightly flexed to fine-tune the edging, but the skis are tilted up less with the knees. Rather, you gain a high edge because the hips are well inside the skis' arc (B). The outside leg stays relatively long and acts like a shock absorber. Stay balanced against the middle of the outside ski, and ride it around the corner (C).