I would like to share my experience with CCSP examination. I already have CISSP certification which helped with many topics while preparing for the exam. Also, when you have moved a mountain in past, moving anything big feels easy compared to that.
My experience with (ISC)2 certifications has been different, where just mugging up study materials don't help much and you need to have good analytical and logical thinking capabilities as well. This is where having years of real experience in your domain helps, where you have faced similar business decisions and have been exposed to similar architecture/solutions in your career.
Said that, I will recommend for aspirants to read The Official (ISC)2 Guide to CCSP CBK at least twice, though this can be very mentally challenging as the book turns repetitive and randomly organized at places. Here comes the most important part, while revising the topic place yourself in shoes of different roles e.g. Business Owners, Security Architect, Data Custodian, Cloud Service Provider (CSP) and think what would you do given the situation. Simple example can be what would be your criteria while selecting a CSP for your Enterprise. Add gradual complexity to your requirements and see the solution changing.
I will also recommend the CCSP Official "Study" Guide by O'Hara and Malisow for reading. You will feel at so ease and it will be fun, believe me after finishing the above Guide. The chapter make short reads and has "Written Labs" section pointing to resources and prepares you for above pointed "wearing different hats and think what would you do" part. Don't forget to google where you don't have ample material in books as things keep on changing constantly, GDPR is about to come in action and more important/relevant than warranted in book. Same goes for Privacy Shield.
I didn't went for any separate practice tests and just did the exercises at the end of each chapter.
Hope I was of some help for CCSP Aspirants. All the best with preparation. -- Krishna Pandey