If you want to improve your ski fitness, you might want to look into ski-specific exercises. There are some good ski simulators that will help you improve your carving ability, even when you are not on the slopes. These are great for the off-season.
Many of these simulators help you improve your balance and endurance and coordination. Not only are they effective, they are also very fun to use. They are much more effective than mere cardio, because they targets ski specific muscles. They focus on strengthening your elbows, knees and the whole body motion. They are able to be used either in your house or at the gym.
They really work
Many skiers have seen these machines, but are not sure if they are really effective. They definitely do work. This is evidenced by the fact that they are used by a lot of ski teams and schools, as well as ski clubs around the world.
If you are interested in ski fitness, the PRO ski simulator (www.ski-simulator) is one you want to consider. This one is very versatile, because you can vary the resistance level to fit the slope you generally ski on. Therefore, you can target it based on whether you prefer gradual or steep slopes. If you want to get ready for skiing even in the middle of summer, this is a machine you want to use.