Sister! visit this section http://www.cssforum.com.pk/off-topic...commendations/
Here you will find some good books seniors referred. But don't spend a lot of time on these extra books and novels because you have to read a lot of books for your CSS compulsory and optional subjects. So just visit sections of each subjects and there you will find out the books seniors and CSPs refer. Buy some of them and start reading them. Even you can start making notes for yourself. Moreover, read daily Dawn, The News, Jahangir Worldtimes' monthly magazines either online on their site or you can have a hard copy from any bookshop.
Good luck.

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"Whomever Allah guides, no one can misguide, and whomever Allah misguides, no one can guide." Al-Qura'an.