You will be asked to perform a reverse around a left corner in the driving test. The first thing to do is to look all around before you reverse. There is no need to indicate because your reversing lights will come on.
Keep it slow using clutch control and look behind more than the mirrors. You should look over your left shoulder but make sure to get a right shoulder check before you begin to turn the wheel as well as two more right shoulder checks on the bend. You can look in your left mirror but only briefly in order to line up the kerb with the side of the car. If you lose sight of the kerb don't worry, this is normal and it means you are not close to the kerb. If you can't see the kerb then keep steering gently and when you do see it re-appearing then straighten up.
If any vehicles approach from behind you should stop and let them go, if you find yourself stopped in the middle of the bend and you are causing an obstruction then the most practical thing to do is go back to the start and begin again. This will defuse the situation and allow other road users to proceed.
Be aware of how your back wiper and back demister operates as these could be handy in case of bad weather as they will enhance your visibility. Try to let down the windows slightly as this will help you hear a bit better. Very often you will hear something before you see it.
The steering you use is important. There is no need to steer fast and get quick full locks on the wheel as this could cause confusion and perhaps encourage the car to weave in and out. Gentle steers is best especially at the end where small corrections is preferable. Keep reversing until the tester tells you to stop.
So keep it slow, look behind mostly and gentle steers.