Pointers for Google Certification Exam

I am a Google trainer, and I failed the re-certification exam after four years of teaching. Now I am done with this embarrassing confession. I asked my colleagues, also trainers. Here I am collecting their advice, with my comments.

1. The exam got harder. Be humble and prepare for the exam.
2. Study Google documentation, in particular, the description of the companies on which the questions are based.
3. Cloud Guru course. It is two years old and has a 2-hours practice test at the end. Add your own knowledge and experience that you can get from QwikLabs.
4. Question dump - you can find them on the web. They may be outdated and (very importantly) give you the wrong answers. At least the Apigee test dump was that way.
5. Good luck!
6. I passed, so it must have worked.