Sorry to hear about your near miss. Assuming you have a reasonable grasp of the knowledge in the syllabus, I think you need to practise questions. Many of the multiple choice questions are very tricky, to the extent that I think some are a bit sneaky or depend too much on interpretation/judgement.
There are some tests on this site, but to get lots of questions, I think you should try to buy a revision kit from BPP, Kaplan or the like. Don’t mark your answers on the book: use a separate piece of paper, then you can keep retrying the tests without clues form previous attempts.