In order to enjoy even recreational skiing properly, you need to be in pretty good overall shape. Ski training has developed in recent years, and technology can now be combined with good old fashioned hard work and training methods to produce better results for skiers who are serious about their fitness.
In order to stay out on the piste and make the skis do want you want them to do, you require a good degree of physical strength in your core and legs. While some weight training can help with this, other exercises which use your own body weight are also useful. Core strength can be built using push ups and sit ups.
Sitting against a wall as though you were in a chair and supporting yourself by your own strength is also a good exercise. You can hold the form for as long as is practical, repeating the exercise several times each day. This will strengthen hips, thighs and your abdomen, making skiing much easier.
You also need aerobic and anaerobic fitness to be a good skier. This is how well your cardiovascular system responds while breathing and not breathing, basically. Running is a great exercise to boost cardiovascular fitness. If you run intervals of short, intense sprints, with short intervals of rest between each sprint, then you can boost your anaerobic fitness too.
A major new way of training has been seen in recent years with the development of ski simulator machines though, which replicate the movements of skiing in the way that a stationary bike replicates cycling. These devices really are the way forward when it comes to home ski training. Check them out online and in your local ski store, where you can also ask for more advice about training.