here is my experience.
i am a government in Police department.
while doing job i started my Master in English Literature and passed it with distinction i.e. i was awarded Gold Medal by the university in 2012.
after that i prepared for CSS exams and appeared in 2013.
i am hopeful about my success.
i just want to say that dont leave your jobs, prepare for your css exams but i needs time management. if somebody wants some suggestion about prepration alongwith job, can email me.