Its 9 PM the night before a big test and you are completely unprepared. The only way to salvage your score will be to cram like your life depends on it. I was guilty of many late night cramming sessions in College and always managed to salvage it using the following tips.
First, you want to eliminate any distractions. You are already low on time, and cannot afford to lose anymore. Turn off your phone as well as any social media sites like facebook.
Next make a to-do list of the most important and weighted topics in the exam. You will want to focus on these. For example if the exam will have a random essay portion you will want to consider if its worth to spend time researching every topic, or just focus on what you know will be on the test, like the basics for multiple choice.
The to-do list will keep you organized which is the most important way to be time efficient. As you finish each new item cross it off and pat yourself on the back. Leave a tick mark next to to-do items you aren't sure about yet and revisit them again later.
If you are feeling really rushed for time you can use a home work and test help site like course hero or chegg. These sites can be considered cheating however some may have answer keys to your very exam! Students who have taken the class before you may have uploaded the test key. If the answers are uploaded you may need to pay for access. However you can also use common course hero hacks and get course hero free by looking for tricks online.
Don't forget to supplement your study night with coffee and energy drinks. Eat nutritious foods that will give you energy for the big exam in the morning. Using all these techniques should help you get a slightly better score in the worst case scenario of needing to cram the day before.