Oh how I am loving Gen Nav!! Exam in Feb and slowly getting there! My biggest top tip is put down your course books and go straight to the Bristol GS Question Bank. Start from question 0 and go through all 568 questions time and time again until you are nailing them.
On the questions that you cannot do then go into the books and figure out why you couldn't do it, what you need to do and understand how it works. Next time you get that question or one like it you will have a better chance of getting it right. Do this over and over again and you will start building confidence and before you know it the exam will be a doddle!
After you have nailed all 568 questions start doing mock exams. I am on this stage at the moment and getting anywhere between 77%-95%. Just about to start another couple of mocks for today's work.
If you get really, really stuck and you just cannot work out how the answer was derived then this is the time to go back to your school and ask the question. You are paying them after all.
I found this approach work for all my phase one exams and I got an average of 98% across all 7 exams.
Good luck. If you have any specific snags feel free to PM me as I will be working on Nav until this Saturday when I plan a weeks break!
Cheers
NGB
