Organic Chemistry, just a subject dealing with Carbon Containing Compounds, yet considered humongous. (Actually it is)
For NEET, theory you have to study NCERT thoroughly and MS Chauhan/Solomon Frhyle/RK Gupta (only for reference and important reactions), for MCQ you can use MS Chauhan for NEET/AIIMS, NCERT Fingertips and PYQs are must.
Firstly, Classify this subject in 5 extensive parts :-
A) Basics /Pillars of Organic Chemistry
IUPAC Nomenclature, Isomerism (Structural and Stereoisomers) and General Organic Chemistry ( Inductive Effect, Resonance and Mesomeric Effect, Hyperconjugation, Electromeric Effect , Aromaticity , Acid and Basic Strength, Stability and Heat of Hydrogenation).
B) Terms used in Organic
Electrophile, Nucleophile, Carbocations , Carboanions, Free Radical, Carbenes and Nitrenes. Reducing and Oxidising Agent , Reaction Intermediates, Homologous Series
C) Reactions and their Mechanism
Substitution Reactions due to Nucleophile (SN1 and SN2) and it’s governing factor like kinetics (order and molecularity), For eg Reaction of Alkyl Halides and Alcohols.