Three things carry equal importance in preparation of CSS exams.
1) Proper Guidance
2) Time Management
3) Hard work
Ignoring or not giving due importance to any one among these means u wl not be in a position to exploit ur potential fully.Chalk out plan to study almost 8 to 10 hours daily.Don't expand the stdy of a single subject to affect the timing of other subjects.
Guidance from seniors is most important of all.Prayerize ur efforts to Allah Almighty.hope the best