My lessons learned dont vary much from others here. I just wanted to share some perspective while its fresh on my mind.
Pure memorization is not my strong suit, and I found that simply reading the PMBOK wasn't getting me very far early on. I shifted my approach and focused on answering as many sample questions as possible and used each wrong answer as an opportunity to take a deep dive on those areas that I missed. This helped me develop some context to the content I was reviewing and was actually rather enjoyable compared to reading the PMBOK page-for-page. I relied solely on the PMP Exam Simulator and, as many have said in this forum, I found it to be very comparable to the actual exam in terms of style and difficulty. Fortunately I had some time between projects and spent a total of 4 weeks studying for the exam.
My biggest struggle approaching the exam was accepting that I was ready. The variation in my performance across process groups was the primary cause to my concern, but I trusted that fact that almost universally every says to target an 80% (even though it isnt guaranteed you'll pass) as an indicator of your readiness.
Practice Exam: Tot%, I, P, E, MC, C Proficiency
1: 84% B, MP, MP, P, P
2: 79.5% P, B, MP, MP, MP
3: 82.5% P, MP, MP, MP, P
4: 85.5% B, P, P, MP, B
9: 83% P, MP, P, MP, MP
8: 82% MP, MP, B, P, P
Actual exam:
I: MP
P: P
E: MP
MC: P
C: MP
From my practice exams I knew that I generally started off a little sluggish first thing, so the morning of the exam I went to starbucks and reviewed my brain dump and went through a handful of sample questions. This really helped me get into the mindset of the exam. I arrived the test exam center early and was fortunate enough that they let me start early. Based on the change in the policy to eliminate brain dumping during the 15 min intro session (the testing center did specifically call this out FYI), I opted to forgo the brain dump. While I would have had plenty of time (I finished the exam in just over 3 hours), it was fresh enough on my mind that I was able to recall the info without having written it out.
Best of luck!