dear few issues are to be prepared by background/historical point of view to make the concept of question elaborative while others are hot issues which are usually from current time.
e.g how kashmir turned to be a dispute is a common question which v shud know before going into details of kashmir disput's current scenario.....same is the case with palestine dispute. for these kind a issues u must have background.
While for issues like K.L BILL or NFC at gawadar port or accountablity by suomoto notices.....these r burning issue which u have to do in any case


so ill prefer to guide you to do first most repeated topics throughout past papers,then pakistan and regional issues and then come to current issues like i mentioned above
this way you can keep yourself uptodate and prepared for not only c.a but p.a and essay as well.......
but don forget to keep bird's eye view of DAWN the Giant for CSS