(Original post by ArtisticFlair)
People like you are really unlikely to go to Oxford; firstly, you've made it clear that you want to go to Oxford, but not what subject you intend to study. You need to have so much passion for that subject, and from reading your post you obviously have little interest in the subject: you just like the idea of actually going to 'Oxford', not exploring and researching your subject.
Secondly, you've chosen stupid A-levels; Media, Business and IT are going to get you NOWHERE in life. You certainely won't be able to go to Oxford with those subject choices.
Thirdly, you feel the need to declare that you go to a 'comprehensive school'; I too go to a comprehensive school, but I wouldn't go into my Oxford interview and say 'Oh, I'm amazing AND I go to a comprehensive school'. You would just sound conceited.
You also need about 7A*s as a minimum to be seriously considered; you can get in with lower than that, but you need to have a serious interest in your subject, which you don't seem to have...
GCSEs, however, say nothing about your ability at that subject, and I know people who get A*s in English yet got a C at A-level, because GCSEs are basically just memorising an essay a teacher gives to you.
You say you like to 'pre-plan', but Oxford like candidates who think on their feet, are articulate, and who are spontaneous... if you're going to take 10 minutes to string together a sentence or form an opinion on how Dickens explores self-improvement in Great Expectations, for example, the tutor would have probably decided that you're too weak for the course.
I'm not at all trying to be rude; you've asked for advice and I'm giving it to you. I think that if you act on my guidance and start reading around your subject in depth, you stand a very good chance. Good luck!