dear, Fawad first of all best of luck for ur css studies.
for increasing vocabuarly u can check these useful tips.
http://www.cssforum.com.pk/compulsor...ng-skills.html
http://www.cssforum.com.pk/compulsor...ocabulary.html
And ur combination of optionals subjects is pretty good.ur three subjects matches with mine that is Ido-Pak history, journalism and sociology.by taking Indo-Pak. history u will be well versed with Pak.Affairs also and journalism is a subject which can be prepared in just 15 days if u dedicate those 15 days only for it. i had sociology during my graduation and its very easy subject and helpful also in essay writting.
For guadiance and books for sociology check this
http://www.cssforum.com.pk/general/o...sociology.html
for const.Law
http://www.cssforum.com.pk/general/o...sociology.html
this forum is full of tips, experience and guidance.........first u should go thorugh its threads regarding guidance and books selection .
i hope it would be of great help to u.
take care.
good luck