I have a theory: most people don't know how to teach. So while most people know how to drive (and some of then are excellent drivers), they can't really teach anyone - thus the subsequent "fights" between couples and parents/kids and whatever.
This is why you hire a driving instructor. Because he knows how to teach and he explains things to you - the things that all the drivers already know instinctively. Your instructor would be able to articulate all of that perfectly. So you would not be fazed as to where you went wrong.
A good teacher/instructor tells you HOW to do things. Like you are meant to indicate first, then put your gear, then release your handbrake and check your mirror (centre first, then the other two) and then your blind spot, and then you can do. All of you drivers reading would go "duh" - but someone who is learning can benefit from this - and that is the whole point of learning.
He is also the one who would tell you, this is how to position your car when you turn. This is what you do - indicate, then 10 m before you start changing lanes, check your blindspot, then make sure you follow the rules (stop sign or whatever), then follow the line.
This is what you do in a roundabout: slowdown, quick check to the right, then move.
This is what you do when you are changing lanes: indicate, check mirrors, blindspot, then change lane.
Man, he is worth every penny. I swear I should be spending my money on practical skills rather than sitting in a classroom for more brain exercise.
Driving is cool man. It is fantastic for a control freak like me.