One of the techniques our teacher used to help develop our paper 2 skills in English was to give us a part of an IB question which focussed on one literary aspect. Then she would give us 15 minutes to write up to 500 words on that topic and then grade it by IB standards.
It was her way of quizzing us (or as we thought of it, torturing us). This essay prompt was finally the one I got right midway through IB Year 2. The questions was to characterise eccentricities or duality in a character of one of our books. I picked Shakespeare and analysed Gertrude.
This paper received a solid 7 because it had all the pertinent IB analysis in/under 15 minutes, and showed what set of skills one needed to possess to thrive under exam conditions.
I would suggest that if you think that you write well in general, but the times exams are too much for you, this technique would help you heaps and you can hold this response as what a 7 in this technique looks like. If you master this, your Paper 2 (and to an extent Oral Commentary) will suddenly become a lot easier. That I can guarantee from experience.