I have said many times that balance is the key to skiing. Since you are constantly moving over changing terrain, this balance is not static and is something that you must always strive for. Therefore, moving can help you stay over your skis. Next time out, make some nice long radius turns. At the end of each turn take two steps up the hill before making the next turn. Keep on practicing this way and then after a while try making steps down into the fall line to your next turn. Work your way up to stepping all of the way through your turns and strive for consistent speed in steps through all of your skiing. Start on easy terrain and then challenge your way up. If you can step through turns on a black diamond, you will be that much better of a skier.