Use of signals
A surprising amount of driving tests are failed due to the overuse, lack of or incorrect use of signals. Even what might appear a minor issue such as forgetting to cancel a signal after exiting a roundabout can easily fail a driving test.
http://www.drivingtesttips.biz/when-to-signal-when-driving.html
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Indicator Lights
Left rear indicator
Indicator lights are amber in colour and can be located at the front, the rear and sometimes at the side of the car on both the left and right hand sides. You use your indicators to show an intended change of direction, whether turning left or right or moving out into traffic.
You only need to use your indicators if other road users (vehicles, cyclists or pedestrians) are visible.
http://www.driving-test-success.com/driving-articles/signaling.htm