There are certain things in life that you plan to do for a very long time before you actually get around doing it. In my case CISSP is one of these things that I have thought about doing for more than five years but something has always interfered. In December I finally managed to attend a test and it went well so now I am a CISSP.
I actually didn't study very much for the test as the twins eats most of my spare time. I did take the time to read through Shon Harris All In One Exam Guide which I think helped quite a bit. Really good reading and actually worth taking a look at even if you are not going up for a CISSP.
The best piece of advice I got was to remember to bring some snacks and something to drink. The exam is six hours and you really need something to keep you from keeling over of exhaustion. It was many years since I have ever felt as totally knackered as I felt after the test.