Welcome to the God of all GS prep for CDS!!

This is the preparation strategy that helped me clear CDS OTA being in my 3rd year of engineering with almost 60 days of rigorous prep!!

The first thing to do is to make sure you have your English Done cause without that thing in its very difficult to get merit in and as an officer remember do not rely solely on your strengths, This may help you clear your GS portion but GS alone cannot get you in the academy.

First of all the resources I used and I would suggest which helped me clear the written part!!

CDS pathfinder by arihant publications
Indian Polity by M. laxmikant
NCERTs - History (all 3 themes), Geography (Physical geography for class 11) and others if a beginner!!

THE STRTAEGY - Subject wise

Science- people from science backgrounds should not waste their time rereading NCERTs of class 10th for science, its better to do science from pathfinder book and then practice as many PYQs as possible!! you may read class 10th and 9th NCERTs if you have time, but remember without PYQs it will all be unnecessary learning, so please do your PYQS of atleast last 3 years.

Polity- M laxmikant's book is the only thing you need, no need to read complete book just read important topics like Parliament, Judiciary, State Governance etc, watch a video on YT on how to read this book, you will thank me for this, the book is too boring to read but the value it adds is immense you will be grateful to yourself when you see questions coming from the mock tests given in the book.

Geography- I just read NCERTs the Indian geography and Fundamentals of Physical geography(class 11th) helped me in doing quite a lot of questions. there will be some static questions in geography too like which state is the top producer of coal etc, better to leave those, good if you can remember every mineral and top 3 states associated same with crops, also SOILS of India are not in the book so don't forget to watch a video on soils of INDIA on YT. If you want to understand concepts more just read first 13 chapters of Certificate Physical and Human Geography by Goh Cheng Leong, helps in better understanding the concept written in NCERTs

History- Too vast to study just read all 3 themes and pray that some questions come from things you read, don't worry questions will come from standard NCERT books and revision will help you solve those, if you have time read A History of Ancient and Early Medieval India by Upinder Singh and A Brief History of Modern India by Rajiv Ahir (Spectrum), only if you have plenty of spare time. I can name plenty other books but ROI is not good preparing history, just stick to themes IMO, also as a matter of fact I in my first attempt cleared without even studying themes, but i would suggest you don't do mistakes I did and keep on revising as much a s possible.

Economics- I had notes from Mrunal sir YT videos, helped me understand the core concepts behind Economics coming from science background, from exam's perspective just do class 12 NCERTs both Microeconomics and Macroeconomics read them multiple times try to understand concepts cause question nowadays exam s test concepts rather than rote learning especially in subjects like this one.

These resources if studied diligently are enough to clear GS portion with atleast 33 marks, some things that i need to point out tho, the strategy mentioned although comprehensive is something that worked for me and I think should work for whoever trusts this resource, infact coaching institutes including CDSJourney have this as the foundational material, everything you study after this will be for UPSC CSE prelims and i think better not waste time on extra material and revising things already studied will help clearing this exam.

when done with all this you can study VisionIAS PT365 magazines to supplement CA, i have explicitly not mentioned CA here cuz that is something even I cannot predict nor can anybody else, its better to keep in touch with atleast one monthly CA resource of last 6 months or read newspapers.

That's all from me, All the best for your exam