Hi there!
First strengthen your concepts in organic chemistry.After you do that you need to practice questions.
MS Chauhan has very good innovative questions. You can practice from that which helps you strengthen your concepts. You can practice JEE version if you are aiming for AIIMS. (Update: There is no more AIIMS exam now. So I recommend solving MS Chauhan for NEET)
But honestly speaking about 1–2 questions in NEET are from OP Tandon IIT version. These were difficult and controversial questions. You can solve them if your questions are strong. But the question Bank in OP Tandon is vast. You can atleast do the MCQs of few important chapters. I would suggest not to read the theory of OP Tandon.
In my NEET Paper there was a chemistry question which I attempted wrong and only after coming back I realised that this question was there as it is in OP Tandon.
But I also practiced few questions from my friends MS Chauhan and found them extremely useful. Though they were not ask directly in the exam they helped me to strengthen my concepts.