There are plenty of good books on Pakistan Affairs. I preferred Trek to Pakistan, Pakistan Studies by M. Ikram Rabbani and lectures from different YouTube channels (Pakistan Study lectures by Dr Hasssan Askari Rizvi on VU page). Read at least one book on Pakistan by any author (e.g; Pakistan is a Hard Country by by Anatol Lieven and Pakistan in the Twentieth Century by Lawrence Ziring). Try different sources for preparation. One thing you must not do is rely on others' notes. I've always believed in spending quality time on preparing my own notes and have scored 55+ in Pakistan Studies twice. Believe in yourself and never look back.

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“What we need in this country today is more courage and more belief in the things that we have.”- Thomas J. Watson