yorickYou can get them stoneground. Ski shops have a machine that consists primarily of a circular stone that puts an identity (think small little lengthwise cuts) into the bottom of skis in order to create a little air barrier between the base and the snow and therefore reduce suction drag. You'll notice on race skis that the bottoms aren't flat, they have this identity cut into them for this reason.
As I understand it, this isn't done to twins, kids skis or snowboards because it makes the ski want to track more straight, reducing the ability to pivot and slide around.
Also wax like mad.
This is it. It's called a structure and it's done to all skis and boards. The structure can be altered depending on the snow conditions. Like wax there are differnt structures which will suit different snow types. But you don't need to worry to much about getting the correct structure all the time, so long as there is still somthing on the base they will run better. From there it's base treatment. Waxing every couple of days with the correct wax for the conditions will help too. Never use any solvent cleaners in the base. You actually want to build up the wax in the base not remove it every time you rewax.
So go chat to a good shop about getting a base grind and then a stone grind to restructure your bases.