Method #1: In a straight line:
Position your car so that you are facing away from the space, trying to get the space you want directly behind you. Then use the centre point of the rear screen (silver sticker in our car) to line up with the centre of the space, as you look in the interior mirror. Make sure the area is clear, particularly centrally behind, by looking over your left shoulder, check your right hand side too. Then begin to reverse. When you get close to the space - stop & ensure that you have a white line each side in the side mirrors. If so, keep straight and continue reversing. Stop when the car is fully in the space, usually best judged by looking at the line at the front of the parking space next to you.
Method #2: At 45 degrees to the left (photo below):
Drive forwards towards the front of the space you require to reverse into. When your front is level with the space, check your mirrors, and steer away from the space at about 45 degrees. Pull far enough forwards so that you can see the line at the side of the space you want in your left side door mirror. Check over your left shoulder. Check all around. If safe, begin to move back keeping the line you want on your left in view, but close to the side of the car. Ensure that the line is always visible. As the back of your car enters the space, check for a visible line on the right side too. Then straighten the steering to keep parallel to the line, probably only about three quarters of a turn. Move fully back to finish.