While skiing your ankle should always be a bit flexed. Next time you are on your skis, try it while standing still. When you try to bend your ankle a little in your boot, you should feel the front of your boot. Try to keep this feeling when going down the slopes. When you turn to the right, your should feel the front ride side of the boot. When you finish the turn, you should rotate to feel the front center of your boot and then rotate to feel the front left side of your boot.
Just think of smoothly rotating your ankle back and forth across the front of your boot and you will find your self sliding less and carving more on the slopes.