Hello Akash, To give quality preparation for General ability For NDA:

1. Aware of syllabus, types of question they cover and topics they avoid to ask.

2. Go through previous 10 years question paper (To Understand questions pattern)

3. Solve as many as sample/ practice/ mock paper (Will help to generate confidence)

4. Try to solve Online test series (Help you to understand how to tackle queries while under pressure + also help in time management)

5. books - Arihant (Pathfinder for NDA), R. Gupta's (for NDA & NA), Manorama Yearbook (For current affair)

All the best

Hi

First you need to understand the pattern and types of questions asked in general ability for this you can go for any standard books like arihant.second option is online preparation (which is more preferable today )there are many website whch provide guidance for this .Third practice as many questions as you can and final can appear for mock test provided my many websites.

All the best!!

jai hind!