After sitting several security and cloud certification exams, I settled on a study routine that sticks. The biggest change was moving from passively re-reading PDFs toward timed practice questions.
The single most useful habit was doing short focused practice sets every day. I use the free practice tests at https://www.examcert.app/ to drill weak areas. They cover CISSP, CCSP, CISA, PMP and more, and the explanations are what actually teach you.
For domain drilling I go straight to the exam pages:
CISSP: https://www.examcert.app/exams/cissp/
CCSP: https://www.examcert.app/exams/ccsp/
PMP: https://www.examcert.app/exams/pmp/
Tracking accuracy per domain over a few weeks tells you exactly where to spend your final week before the exam. The free question bank is the cheapest way to find your blind spots before test day.