I got an 8 (3 marks off a 9, might remark) and my #1 advice is use duolingo every single day for about 5 minutes, and a bit longer on the weekends. I don't think I would have done as well in the exam had I not used it because unlike other techniques, you are actually learning the language in a more organic manner as compared to the clinical approach of reading a textbook. Also it sticks in your brain because you have to apply information directly after learning it, and you can't learn a language by studying it once a week - it has to be a continual effort or your brain will not remember anything. One note: I recommend having duolingo on both your phone and computer, as on your phone you will have expendable hearts, which is not the case on a computer.