Congratulations, Iman!
That's well worth celebrating. What you describe is essentially what I found worked for me, too. The time taken to read the explanations in depth and to properly internalize the core reasoning is what I found to be most helpful in getting my results average way up, rapidly.

If you have any acquired wisdom that you think would help others, I'm sure it would be very welcome over in the PMP Exam Lessons Learned thread.
Again, well done.

I took months to only do many many quizzes - sometimes 10-20 daily and then spending 3 times the time to take the quiz to read all the explanations. That gave me a picture of what is expected so when I went to PMBOK I went specifically to a section I felt I need to understand better.
I would do many quizzes and then go to a specific chapter or the PM Prepcast video relating to that quiz when you feel it's required.