Best subject combination for engineering students
 

Aoa. I'm a student of 3rd year in Civil Engg. UET Taxila. In the future, I have decided to appear for CSS exams soon after my graduation (In 2018). That's why, I want to start preparing for both compulsory and optional subjects along with my graduation. I want guidance regarding the subject selection. Means, what subject combination is best for students with engineering background?

Thank You!