I did a SANS CISSP prep course, read the official guides and CISSP
Official (ISC)2 Practice Tests. I studied 2-3 hours a night for almost 3
months. The biggest thing that helped me was almost 20 years of IT
experience, so I've seen a lot and experienced the changes in IT over those
decades. Approaching the test from a senior management perspective helped
as well. Good Luck.