thanks vandana mam , here i start with the basic guidelines by you . it is basically the list of books you need before you start . GS sorted .

the context below is by vandana garg mam answered on qoura . 

There are some books which have to be read by every UPSC aspirant. Some of them are as follows and I will try to tell how to study them side by side.

1. Indian Polity by M. Laxmikanth

• It is the most important book. Read it atleast five times before Prelims. No need to make notes out of it. You can mark in book itself. You can make mind maps regarding some topics like where all special majority is required, who all are appointed by President, provisions regarding various bills, removal and appointment of constitutional and non constitutional offices, various Acts passed during British Rule etc.

2. India’s Struggle for Independence by Bipin Chandra

• You can read the book and mark in the book itself. No need to make notes. However, you can also read Rajiv Ahir's Brief History of Modern India in its place. All depends on how much time you have.

3. Spectrum’s A Brief History of Modern India

• Book has itself mentioned everything point wise under sub-headings. It has also given tables at the end for some topics. Overall what you can do is to make notes of important topics like Revolt of 1857, important freedom movements, Acts passed under British rule etc. This is because you will have to memorise many facts. It becomes easy when written in your own language.

4. India Since Independence by Bipin Chandra

• Read the book and mark in book itself.

5. Certificate Physical and Human Geography, G. C. Leong

• Few chapters related to Physical Geography are important. You can directly read from book. You might have to makes notes for those topics you will read from the NCERT, to avoid duplication and have comprehensive notes under one head. The chapters on world geography related to different climates can be read directly from book.

6. Nitin Singhania's Indian Art and Culture, CCRT

• Make notes or mind maps for yourself

7. Indian Economy, Sanjiv Verma and Indian Economy by Ramesh Singh

• No need to make notes. Study and mark in book.

8. NCERT’s :

• GEOGRAPHY - You can read directly from book. No need to make notes unless you are covering same topic from more than one source. These NCERTs are very important. Cover them properly. If you do not Understand something, watch its animation on Youtube. You can refer http://Mrunal.org for some topics.
• Fundamentals of Physical Geography (11th )
• India – Physical Environment (11th)
• Fundamentals of Human Geography ( 12th )
• India – People and economy (12th )
• HISTORY- Make notes, otherwise impossible to memorise
• Ancient India – RS Sharma (11th)
• Medieval India – Satish Chandra (11th)
• Tamil Nadu History (11th)
• Tamil Nadu History (12th)
• INDIAN ART & CULTURE- Collaborate with your already made notes from other sources
• An Introduction to Indian Art (11th)
• ECONOMICS- No need to make notes. Study thoroughly and mark in book
• Indian Economic development (11th)
• Introductory Macroeconomics (12th)
• Introductory Microeconomics (12th)
• SOCIOLOGY- Give thorough reading. No need to make notes. Mark in book
• Introducing sociology (11th)
• Understanding Society ( 11th)
• Indian Society (12th)
• Social Changes in India (12th)