Hi Kawa-4
Fault Identification
Not looking in the direction of travel ie through the back and rear side window as you reversed.
Fault diagnosis
You were doing it either by using only the mirrors or were in a hurry and therefore rushed it.
Fault correction
From now on, you will take all round observations before moving in any direction then look through the back windows in the direction of travel before the car even turns a wheel. As you move the car, continue to look in the direction of travel. You can use the mirrors only as a quick glance - main part is looking to the back.
PDI.