I spent about 6 months studying various subjects just to determine which ones to select for my actual attempt. Among the subjects that I finished but didn't select were International Law, International Relations, Political Science and Public Administration.

In the 20 months that went to actual studying, I read a lot of stuff that wasn't even directly related to CSS. Things like blogs, journals and academic papers seemed more interesting compared to the actual syllabus. I read numerous books on Pakistan's history written by authors from different countries since they all have their own perspective and their unique insights. I read books on Pakistan by American, British, Chinese, Russian, Indian and Pakistani authors.

Also, those 6 hours a day include a couple of hours each day for watching lectures, debates, documentaries and seminars on different topics. Call me slow, but I like to take my time. There was hardly any studying in the last 3 months, it was all practice sessions.