The best thing you can do to improve your score is to ensure your brain is working at "peak performance".
Spend the evening before the exam doing things you enjoy... early movie, dinner with spouse, extended workout at the gym, etc. Then, get a good night's sleep, a good breakfast and leave plenty of driving time.
If getting up early for one last review will help you get in the zone, then by all means do it. However, if it would build stress, get a few more Zzz's instead.
Also, save the alcohol for the post-exam celebration.
A few thoughts while you are in your final weeks of studying.
When I took it, it was from the management perspective. I was a technician at the time and struggled with that. The best solution for a tech is usually the most expensive. The best solution for management is directly related to ROI (return on investment). Get out of the tech mentality. Safety first then money second. Don't think risk elimination, think risk mitigation.
Also, for the test, bring aspirin take it whether you need it or not at the 30 minute mark. it will keep the headache of focusing on a monitor to 2 to 3 hours away from you. Don't be afraid to look away. Research indicates that a change in thought process or diversion every 15 to 20 minutes will help maintain focus on the subject.
Good Luck!! I'm also scheduled to take the exam on 10 April. I found a very helpful site that I'm using to prepare. It has over 1000 questions and provides a graphical breakout of your weak areas. I like the site. You can find it at http://www.cisspexampractice.com. For six month access it costs $59.
Also, check out the Study Note and Theory site at https://www.studynotesandtheory.com/ for CISSP info. This site has a lot of good info to include videos and tips. You won't be disappointed. I looked at the site a little and found it very useful.
I passed last month. Studied hard by reading Shon Harris, RIP, and taking her chapter tests. Had ISC 2 official practice test and took those as well. Previously, went thru Sari Greenes' video which was HUGE help in understanding how this exam words the questions and that she's figured it out.
My head a hurt a lot from studying, I was worried, but took a long walk before the test started, didn't cram or look at any material the day of exam. Was real nice to get the congrats letter when it printed!