All good skiing starts with the feet. Which drills work best for you to concentrate on how you want your feet to move? When the feet are moving as you like, when your skiing at this level has plateaued, move up the kinetic chain. How do you want to move your hips, your shoulders, your arms. How is your fore & aft balance? Do you have a drill to reinforce how you know when you're in balance and out of balance? (I'm thinking of force on the back of the ankle and weight on the heels, vs. force on the front of the ankle against the boot and weight on the ball of the foot. How can you test this, if you need to?) How do you want to re-balance?...drill, drill, drill.
Basic rule: Challenge yourself on either technique or terrain, not both.
The double pole drag is great for breaking the inclination habit and starting the angulation habit. Both poles need to be pressed firmly into the snow while dragging for this drill to work best. While double pole dragging, rotate the body, and arms, and dragged poles, in the opposite direction of the turn to start the counter habit. Don't let the inside foot slide forward, keep the feet as close to side-by-side as you can. Another good angulation drill is to place both poles across the knees nested in the notch just below the kneecaps. Keep them there in those notches. Now ski slowly back and forth across a moderate to steep pitch. You'll angulate just right if you keep the poles against both knees. Skiing without poles with the hands on the hips, thumbs forward is a good drill to practice counter--you can see what you're doing easily. Rotate the upper body, hips upward, in the opposite direction of the turn during the course of the turn. Don't let the inside foot slide forward. Hands on hips with thumbs forward helps to bring the shoulders forward.