Driving experience is the key
Research has shown that it takes at least 4 years to become a safe and competent driver. However, if a learner driver has at least 50 hours of driving experience in a wide range of conditions, in addition to formal driving lessons, then this timeframe is reduced. It's really simple. The more practice a learner has, the safer they will be once they are driving on their own!
You have a key role to play in helping your learner to develop their skills as a driver, but this takes time behind the wheel. Make sure that you make regular time available for your learner to practise driving skills. Driving is a complex task and mastering the skills required is essential if your learner is to develop into a safe solo driver.
Reducing the stress for the learner and the supervising driver
Learning to drive can be a very stressful experience for both the learner and the supervising driver. It is important to be positive and to remember that it takes lots of experience and time to develop the necessary skills to be a safe driver. When possible encourage the learner by pointing out successes and don't expect too much from your learner driver. Remember your aim is to help your learner to become a safer driver by giving them plenty of experience behind the wheel.
It takes time to develop your own skills as a supervising driver and so give yourself some time to become comfortable in this role. Make sure driving experiences are at times when you or the learner are not already feeling stressed. Don't push your learner too hard. Make sure the driving tasks you give them are suitable for their level of ability and experience. Be prepared to stop the car in a safe place and calm down if the stress level rises. Remember that Learner drivers are rarely involved in crashes.