You need to secure minimum 65 to stand a chance to Qualify KVPY SX for the Interview. I would suggest you to be thorough with your JEE Main & Advanced Syllabus or AIIMS/NEET Syllabus whichever is applicable. There are many Online Test Series Plans from Providers like Embibe, Toppr, Allen DSAT, you may consider regular practice during last few months from there.

Once you have done with the Basic Syllabus, you should solve Last 12-13 Years Papers of KVPY SX. Career Point Kota and Resonance have published Mock Test Papers, Solved Papers and Detailed Solutions Book from Last 12-13 years, which are available on Amazon and Flipkart.

Besides this, you must keep revising from Standard Handbooks like

Arihant Physics & Chemistry Handbook

Allen Maths Handbook (PDF Available)

For more information about KVPY SX Preparation do follow the link below

https://learn.careers360.com/science/how-to-prepare-for-kvpy-sx/