I have divided International Relations into two part i.e., static and dynamic. Paper I is the static part and Paper II is mostly dynamic. Paper I is foundational work of IR which includes an introduction, theory, political economy and other fundamental concepts while Paper II is the application of the static part, and questions of Paper II cannot be answered without a sound understanding of the static part.
I have found following books very helpful for Paper I:
1) Global Politics, Andrew Heywood.
This book is the most basic book of IR. Even the simplest terms such as state and politics are defined in the margins. Moreover, it has the best introduction to Global Politics. Please find the pdf in the link below:
https://drive.google.com/open?id=0B2...GpsVDVpeDZPOEE
2) Books that contain articles by different authors such as:
Essential Readings in World Politics, Karen Mingst
Globalization of World Politics, John Baylis
Read relative parts only.
3) Perspectives on International Relations: Power, Institutions, Ideas
This book also contains basic concepts; however, it is more advanced than Global Politics by Andrew Heywood.
Finally, I believe reading scholastic articles and keeping up on the news from various different publishers is the best way to stay informed on current situations (Paper II). I am collecting scholistic articles, and I will share them in future.