Physics is a subject where you need to clear the concept first for every single topic first. Without clearing the basic concept you cannot able to solve any problem properly.
Here are the tips:
1. Complete NCERT first, clear all the basic concepts first before start solving problems.
2. Make a formula copy after finishing every chapter. This way it will be easier to remember.
3. Solve the question paper as much as you can. Download NEET 2020 question paper
and try solving them. Nowadays, everything is easily available online.
4. 3 to 4 times revision before the exam is recommended.