I sat the Performance exam today and got 98%.
The exam was very similar to the practice exams. Of the 30 questions, there were 3/4 ETP/PNR questions, around 10 W&B questions and about six detailed knowledge questions.
Some of the W&B questions were not just about the Echo. All types of P-charts were touched on if I remember correctly.
As to my study technique, this was the sixth exam I've sat, with Navigation next, and last. I have studied by myself for all of my exams and have used Bob's books for all subjects, as well as using the exam preps.
Specifically about my approach with Performance, it was repetition. I did about 90% of the questions in Bob's book. This repetition really helped embed the theory and practice of W&B, as eventually what was needed became intuitive. It did help that I am a numbers man first and foremost and I like solving problems.
Consequently, know your flow charts (both the loading and the W&B charts) in your sleep and plot the W&B output on the chart to start with, even if the question doesn't call for it - just knowing where the CoG was to start with helped me understand what the problem was.
Also know the PH/DH calcs back to front - it became automatic for me.
As to exam technique, some questions are straight forward, but some give you more information than is needed to answer the question - make sure you don't lead yourself up the garden path. Bring your own pencils and sharpener as the one provided in the exam is pretty ordinary - I was not looking forward to the linear P-chart. From my seafaring days, 2B is the best type of pencil to use - soft enough to erase completely.
I'm pretty pleased with the result - and is a relief after getting 66% in the timed exam in the exam prep the night before - but better you make those mistakes and learn from them when you have a chance to redeem yourself.
As to the question I got wrong? Let me say that I now know a lot more about the dimensions of the runways at a major metropolitan airport
Good luck and safe flying.