Following are some of the books & tips which you can follow on your convenience for different sections:
The areas to be covered are the history from ancient to modern period. The basic understanding can be obtained from below 10th NCERT books. The focus should be on modern Indian history, which is covered in the mains. The basic knowledge in Ancient India and Medieval India is sufficient.
The NCERT books (Class XI and XII) are good enough for the purpose.
You can refer following books:
Ancient India , NCERT Class XI
Medieval India , NCERT Class XI
Modern India , NCERT Class XII
Modern India, Spectrum publications
The Constitution and various related aspects should be done well. Some articles and facts should be memorised. It is better to prepare this area well since it will be helpful in mains and interview.
The Indian Polity by Lakshmikanth and NCERT books are sufficient. Also refer, DD Basu.
For Indian Geography:
Physical Geography of India, NCERT Class XI
Land and People, NCERT Class XI
For World Geography:
General Studies Manual by TMH or Spectrum Publications.
For Both Indian and World Geography, follow Prelims issues by Civil Services Chronicle Magazine or Competition Wizard Magazine.
The basic concepts are being asked along with current affairs based questions. The basic clarity can be obtained from the standard books. The current affairs can be studied from Economic Survey and the newspapers.
Dutt & Sundaram or Mishra & Puri or IC Dhingra
Some times the questions are asked very difficult that even science students find it difficult to answer. But the preparation should be in such a way that all the basic questions can be done correctly. The questions are also asked in applications orientation.
Science and Technology, NCERT Class IX & X
What, Why & How books by CSIR.
This has become a very important component. The notes should be focused on the factual aspects that come in the news. Many questions are asked from this area, so prepare thoroughly. The efforts will be useful for all stages of the exam. It should become a part of your daily routine.
The Hindu News paper
Competition Wizard or Spectrum Issue on Current Affairs – This is just to make sure that you have covered all the current affairs issues in News Paper.