Just a few notes from my experience through the process of attaining my PMP certification. I passed with 1 Proficient (Monitoring & Controlling) and 4 Moderately Proficient (all remaining).
1) Plan your work and work your plan
Much like the PMP processes lays out, develop a plan. I would suggest that you be very realistic when planning your time. Initially, I thought I would finish the review in 60-90 day: it took a total of seven (7) months before I felt ready. If it takes longer, don't beat yourself up, every path is different.
2) Track your progress
The best thing you can do for your confidence is to track your progress on each quiz and full-length exam during your prep. Intially, the numbers won't be good, but with time, you WILL get better. I kept each group of quizzes/exam tracked in an Excel spreadsheet. By doing this you will see those areas that you tend to be better or worse at over time. Best thing I did.
3) Put in a little time each day
I read the PMBOK guide 3 times, reviewed ALL videos supplied by the PM Prepcast and read Rita Mulchay's book 1 full time and used as a reference. I could not have done that without consistent prep and review on a daily basis. Spending at least an hour a day is manageable. If you are really dedicated ... put in the work.
4) Practice, practice, practice
Take, at minimum, 3-6 full-length practice exams! I purchased the PM Prepcast Exam Simulator; what a GREAT purchase. Not only did it prepare me for the exam experience and types of questions I would be seeing on the exam but those practices also provided me with the level of confidence to "know" I had a grasp of the material and understood how to pass the test. My average score on the 6 exams I took was 79%.
Good Luck to all and hopefully these lessons learned helped.