Thank you for your question. 

There is no fixed method to excel in any examination. 

Every person has their own methods. 

However, there are some recommendations-

1. Read NCERT biology thoroughly and repeatedly. Questions directly come from NCERT books

2. Practice numerical, derivations in physics. Optics,magnetism and nuclear physics are important. 

3. Organic chemistry,  coordination chemistry is important.  Practice numerical as well.

In boards , you have to get 50% to be eligible for NEET.

You can read Pradeep physics and dc pandey to get through the exams.

Good luck