One important thing that candidates should keep in mind is that since the time between the Main Exam and the declaration of result of the Preliminary Exam is very less, it is advisable to begin preparations of the Main Exam along with the Preliminary Exam.
The General Studies paper covers the following areas:
General Science; Current events of national and international importance; History of India; World Geography; Indian Polity and Economy; Indian National Movement; General Mental Ability.
For this section, it is important to be updated in all fields. For History, Economy, Polity, etc, it is advisable to read Class 11 and 12 books published by the NCERT. Some books on the freedom struggle are published by the National Book Trust. For general knowledge and objective-type questions, refer to General Knowledge Refresher by O.P. Khanna. For General Mental Ability and current affairs, it is advisable to read The Competition Master regularly.
One question that is often asked by students is about the subjects that they should take up. Since some subjects are scoring, students wish to opt for them. But one thing that must be kept in mind is one's aptitude. If one has studied a subject since school and one is comfortable in it, chances of doing well in it are greater rather than taking up an unrelated subject which one may never have studied. Generally speaking, do not choose an entirely new subject in which you will have to work very hard. If the optional is prepared well for the preliminary and the same subject is also planned to be opted as one of the optionals, it is very useful and saves a lot of labour.
Once you have decided to appear in the Civil Services Exam, preparations should start early. A look at past papers helps get an idea about the kind of questions that are asked. Over the years, The Competition Master has published solved papers which can be referred to. It may be advisable to join a coaching institute so that one keeps in touch with other students and discuss issues with them. It is important, however, to select a good institute. However, one can be successful by self-study also.