My personal experience and what I was advised to do by my CFI. Get my PPL exam out of the way before I started my navs. If you are good with the books it will actually make the practical side pretty easy...AND...if you have a list on the KDR, it will give you some time to swat up on it because your examiner WILL ask oral questions regarding those deficiencies. Best advice for the actual exam. READ THE QUESTION COMPLETELY. and do a lot of practice exams leading up to the booking.