I was going to say much the same as you Honeyflower, martianbishop obviously came into teaching with more skills and maturity than most.
I became a teacher becuase my education was my escape route from a miserable existance, and I wanted to be able to help other kids take the same or similar path to myself. I chose RE becuase my degree was in theology, beyond that I had not thought much more. RE is a strange subject as once you start working you may be te only specialist in the school so your PGCE is a unique time to develop your thinking that may never happen again except for the odd bit of hurried INSET. You are also not bound by a national curriculum ( although there will be a locally agreed one) or SATS which brings great freedom but also great margin for error and feelings of uncertainty. There are fewer right or wrong answers, how do you give someone a mark out of ten for describing their beiefs?
I am lucky in that I teach part time so I have the time to be a reflective practioner, contemplating how I can iprove my puoils learning, considering what it is that I am teaching and the reasons for it. I have time to keep up with my reading into the latest research - but when I taught full time I just did not have the time to do this.
AS for teaching how to teach I don't think you can, I can remember in my PGCE interview the tutor asked me what I hoped to get out of my PGCE. I said I am bringing my subject knowledge and you are going to teach me how to teach. He told me I was wasting my time and he was right, you can teach someone to be an adaquate teacher and you could teach a great teacher to become an even better one. But the best teachers are naturals, it is like acting you either have it or you don't. Great teachers have passion, charisma and presence these things can't be taught.
Becoing a great teacher takes time, and that is part of th4 problem in inner cities, that due to the teacher shortage a good teacher is too quickly promoted out of thir depth rather than being allowed to practice their craft, reflect on their practice and mature.
But while accepting that I am an airy fairy bookish type of person the theory has to uderpin your teaching, yuo need to know why you are teaching a subject, why you are teaching in the way you are and what you hope to achieve.