Short turns are one of the most useful skills to master and could be considered one of the keys to advanced skiing! It's all about accurate and rapid movements - basically maintaining a good technique under control, but with less time to perform each part of the turn! Movements still need to be fluid and even... here are a few tips:
Turn the skis with your legs - not your hips or shoulders. A solid, centred stance (not too wide) and good edging movements from the lower leg will allow your legs to make all the movements and help keep your upper body still.
Transfer pressure evenly and rhythmically from ski to ski. Edge your skis by rolling your ankles and knees as quickly as possible after you make the shift to your outside ski.
Start on very gentle terrain so you can work on the timing of your movements and turns without picking up too much speed.
Keep your weight over the centre of your skis, enabling them to rotate easily beneath your feet - excess forward or rear weighting will cause your skis to drag or skid.
Keep your ski poles moving - think of having a pole in the snow at all times. This helps to both anticipate the next turn, and establish a rhythm.
Have a look at the Pole Planting tips for more help with your short turns.