Proper guidance is part and parcel of CSS preparation, especially for the selection of books and optional subjects, its importance cannot be overrated. A good mentor can drive one to success; nevertheless, the aspirants must work hard. Although guidance does play a critical role in CSS preparation yet hard work on ones' own part has no alternative. Truly said by a Persian poet:
Tarash az teesha-e-khud jada-e-khweesh
Be rah-e-deegran raftan azaab ast
(Carve your way through your own chisel; following others' path is curse)