dear friend!
though I'm neither senior nor have a good record in terms of CSS exam but I can say one thing for sure that the most important thing about essay writing is to read the mind of the checker which is next to impossible, in CE2009 I got 48, in KPPMS I got 41 but failed that paper (33marks in 2013). so it totally depends about your luck. I attempted the essay on gender and failed to qualify. one thing I must say about my attempt is that I approached the topic in a liberal way and I think that approach has been penalized. some people say that essay is about English writing skills but I've come to the conclusion that it is the content which matters a lot in this paper.

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"Success is not final, failure is not fatal; it is the courage to continue that counts" (Winston Churchill)