I have passed the PMP exam from the first attempt on January 2018. My lessons learned are:
1) Try at least 2 sources to have a broader view on the topics. I used PM Prepcast, Rita's PMP exam prep.
2) Don't read PMBOK thoroughly, but spend 2-3 hours once to go through the book in order to get a general understanding.
3) Don't prepare for too long! I spent 1.5 years to prepare, it appeared to be too much since after a year, I started to forget what I learned a year ago!
4) On the exam, don't bring all the food and stuff: they give you their own water, but don't allow you to eat until you finish the exam.