Balance is the primary skill in skiing.

Pressure scale

Balancing on your toes and heels

Balance is the primary skill in skiing.

I took these sketches from my manual , as this is a good place to start the season. 
When on the hill, an instructor will tell you to have a good centered stance. Translated, this is shown as Neutral in the above left diagram with your weight spread equally on all 4 pressure points on your feet.
The purpose of the exercise here is to feel your weight change concentrated on these pressure points. 
You can practice the following on a hard surface in your bare feet or anywhere else with your shoes on. 

• It is best to first spread your feet apart until you feel pressure only on the pressure points of both feet shown in the diagram. 
• Then move your weight front to back, left to right on both feet, balancing on your toe and heels to feel the pressure change on 2 pressure points at a time.  
• Finally, apply full weight on each of the 4 pressure points. Note how you have to shape your body to make this happen.
• Experiment a bit with your arms out, at your sides and forward; they make a big difference.

You will only be applying pressure one foot at a time; the other foot is used for balance. Balancing is finessing where you shift your body, arms and legs, to apply pressure to your feet.  

Later, when on the snow in your skis and boots, repeat the above with the tops of your boots loose, both standing still and moving.  Boots are different from bare feet and shoes because it is possible to push on the tongue when putting pressure on the toe and on the boot back when applying pressure on the heel.  For a centered stance there should be almost  no pressing on the tongue or boot back. Your body position should be bent at the waist, both forward and to the sides.

When skiing, this exercise is equivalent to what you  feel when tilting your knees in the direction you wish to go. In order to turn quickly and efficiently, you start the turn on your toe pad and finish the turn on your heel. This is a much better method than trying to rotate your skis with your leg. It is called steering and takes a little practice. Maybe a season?  
Balance is the primary skill in skiing. This is just the start.

AlanR.