Where to Hold Your Hands on the Wheel
Traditionally, the recommended position for the hands on the steering wheel was 'ten to two', the position of the hands on a clock showing this time. This position was thought to give maximum control of the wheel and is comfortable.
In the last few years, however, many people have recommended that this practice should be changed. Airbags mounted in the steering wheel can injure the driver's arms as they explode outwards to cushion the driver in the event of a crash. Some think there is evidence that the 9-3 position, which keeps the arms as clear as possible of the path of the airbag, gives less risk of injury. Some car manufacturers even place indentations on the rear of the wheel at these points to encourage drivers to use this hand position.
The jury is still out on whether 9-3 actually decreases the risk of injury, and the best position for maximum control has been debated for decades. If you are just learning to drive you might benefit from not fighting with your instructor and if you've driven for years in that position, trying to change habits might pose more of a risk.
It is a good idea, though, to position the driver's seat well back from the steering wheel and to drive with arms outstretched, because the driver is less likely to strike the steering wheel in a crash. For people with short legs, though, this may not be possible.