Dear Ayesha!
firstly you have to mention about your qualifications, your academic background and then those subjects of your interest
Concept of scoring subjects is like fiction, performance matter in CSS.
But this can be said sane that there are some subjects in which you can get good score if you do hard and smart work.
Such as
Journalism
Sociology
Arabic
Punjabi
International Law
Islamic Law
Public Administration
and some other subjects need a little more effort to get maximum marks
like as
Geography
History of USA
etc etc
Another point, you can save your precious time through opting those subject which overlap like Indo-Pak History can help in Pak Affairs and Geography somehow.......... likewise International Relations can be helpful in Current Affairs and political Science.. etc etc
You can ask any question in this regard