Hey there

To get through entrance exams a lot of hard work is required-

1. Time management: the most crucial part of a students life is time management.know when your focus is good and study at that time .

2.deep study: study's just over the concepts is not enough, if you pick a topic try to get as deep as you can and make sure you get every ounce of knowledge out of it, this method ensures that you understand the topic briefly and you remember it for a long time too.

3.breaks: do not focus on studying for continuously for a 10-20 hours  , that doesn't works. Quality over quantity, that is how much you study and actually get in less time is more important than sitting and studying for so many hours without any focus. Take breaks in between  , it ensures you don't get bored and your focus stays even when you get back after break.

Hope it helps!