Many people drive around with their wing mirrors incorrectly adjusted. In effect, they manufacture additional blind spot space to the rear/side of the car. This increases crash risk, but is easily overcome in under two few minutes.
 
The following mirror-adjustment process minimises blindspots.
 
STEP ONE
Parallel park your car somewhere quiet. Adjust the driver's seat to your optimal driving position.
 
STEP TWO
Adjust the centre rear-view mirror so it gives you the best overall view to the rear.
 
STEP THREE
Pick an object visible to the rear, on the left edge of the central rear-view mirror. Adjust the left wing mirror so that its rear vision just overlaps the object visible on the left edge of the in central rear-view mirror.
 
STEP FOUR
Repeat the process above for the right mirror.
 
CONGRATULATIONS - your rear-facing blindspots are now minimised. There should be a slight overlap between the views offered by the left edge of the central mirror and the left wing mirror, and also the corresponding right views.
 
You might feel as though the side mirrors are adjusted 'too wide' like this. They're not, although it might take a short time to get used to the  new mirror angles. (Many people adjust the side mirrors so they can see the side of the car in normal driving. This, while comforting during reversing, adds to the blindspot problem in normal driving.)
 
REVERSING
If your car has electrically adjustable mirrors, you might prefer to move the wing mirrors inboard and down, to facilitate a view of the side of the car, for reversing. Alternatively, ask a passenger to do so for you, or, if alone, move your head slightly left for a view of the side of the car during reversing.)