It is very important to opt right and effective optional subjects. It seems like If you opt best optional subjects that ensures your 50% success on the spot.
1. First of all select subjects which support your academic background.
Example: Candidate having BBA/MBA Degree may choose Business Administration as the best of the field choice.
2. Select subjects which have been scored pattern. (Note: All Subjects are Scoring, It only depends on you, how you are going to attempt it, So do not waste your time to think about which is scoring or not)
3. Select subject which can over loop another optional or compulsory subject.
Example: If you select INDO-PAK history, it’s part II will cover your maximum portion of Pakistan Affairs and will also lend a hand in Current Affairs. Sociology will also helps you in other subjects as well as International Relation could help you out in Current Affairs.
4. However if you are not finding subjects of your background or interest, then try to opt general subjects such as Sociology, Journalism, any History Subject or any language subject such as sindhi, urdu etc….
This is not the End!
After sorting out your optional subjects, now you have to make a go through their Past Papers and Syllabus very carefully and try to identify your potential about those particular subjects such as after completing syllabus of those optional subjects will you be in position to attempt these past papers easily? If you get a satisfactory answer for yourself then go to these subjects and if not then try to identify other subjects which can best suit you.