I'd suggest you to study earlier in the day because I'm always more focused during that period (when it comes to studying). Also make 5-10 minutes brakes on every half an hour and try to divide the material on couple of parts. Like if I have 100 pages, I read 50 the first day and 50 the 2nd while trying to understand and comprehend the material. The 3rd day I mark the most important parts and try to memorize them by the 4th day. So I usually need 4-6 days to kill an exam. Also remember that when you go to sleep the information kinda lays in to your brain and you can easily recover it the next day, so by the 5th day (let's say the exam day) I have read through it enough times to be able to do a good job.
*the best thing is to study as many days as possible, and it's also easier that way because you can divide the material on more parts and you'll have less pages to cover per day. So if you cut it down to 10 pages a day, that's nothing and there's no way you'll start feeling bored. Plus you'll have more days to read through it and hence memorize it even better.