In order to prepare efficiently for JNU entrance, you will need to study smart. Read the editorial and international relations page of Hindu and IE to get a fair idea of what is happening around the globe. Read Arihant’s guide for JNU entrance for IR. Rafer to some good magazines like Frontline, EPW, etc.
The exam of JNU Entrance would be computer-based and Multiple Choice Questions would be asked. Make sure to study the following crucial portion of International Relations (IR).
The majority of questions in entrance will be from History, Economics, International Relations, Philosophy, Indian Politics, and Contemporary Issues.
Here are some books that you can refer to.
Just prepare thoroughly without losing faith in yourself and be honest with your studies and you shall do well in your entrance.