The candidates for the 2012 IAS Exam should not wait for the notification and should start studying for the exam as early as possible. Start with the NCERT books; these books give you the basics of the different GS subjects.
For the guidance, you should either talk to your teachers, friends or selected Civil Services officers. You may also consult magazines or websites that exclusively deal with competitive exams such as IAS.
Do regular answer writing practice. Make a small group and analyse the previous years’ questions, especially the 2011 GS question papers as they reveal the latest pattern and the thought process currently prevailing in the UPSC and the examiners’ minds.