Have you been given the media text that your exam is on? is it the comparisons?
i cant list codes and conventions because i barely remember them, but what i do remember is that i didnt revise and got good marks (on the AS exams) codes and conventions are common sense, things to look for are like:
twisted camera angles signifying something is wrong or askew
the use of red, showing, passion/blood/lust/anger (Martin Scorsese uses this in most of his films)
the use of other colours,
the use of camera angles e.g. looking down or up at someone, representing inferiority or supremity
Phallic symbols, a killer using a knife for example, mention its a phallic symbol
Try and use terms like semantics, auteur (sp), signifiers, digetic/non-digetic
Media Theories, im afraid i cant rememeber the media theories at all, i think it means thinks like the genre theory in that there is no such thing as a 'new' or 'original' film and that they are just remaking films. This is why they prove to be so popular though, because the audience like to be able to percieve what is about to happen, (Why do you feel tension before someone jumps out behind a door and murders their victim, not because your psychic but because you've seen other films just like it, i.e. of the same genre!)
Good luck, and remember media isnt like maths, there isnt a fixed correct answer, use your own opinions backed up with correct terminology
