Indian Institute of Technology, IIT Bombay

Based on previous year's cutoff trends, you need to have a rank of around 2,000 in JEE Advanced. However, for top branches, you need to get a rank under 100 in JEE.
1. To get into top branches like computer Science and engineering at IIT Bombay, you need to get AJEE Advance rank of around 65.
2. To get into the Electrical Engineering branch, you need to have a rank of around 300 in JEE.
3. In fields like civil engineering, you can get admission with a rank of around 3,000. You can check the closing rank for IIT Bombay at this link to get an idea of the rank you need for admission: https://www.shiksha.com/university/iit-bombay-indian-institute-of-technology-mumbai-54212/cutoff.

I would, like many wise people say, practice reactions, but being a student myself, I know most of us don't spend time looking at reactions, let alone practising them:) In that case, I recommend understanding at least general organic Chemistry including topics like isomerism, stereoisomerism, electron affinity, arrow pushing, hybridisation and, in some problems, MOT. Looking at the reactant, you can eliminate which reactions it couldn't undergo. Looking at other reactants, you may eliminate them further. Then looking at the catalyst or conditions of reactions, you can identify which reactions are possible. Till here, you would need to practice at least a few reactions or have a good memory. It's okay if you don't have it. You can also eliminate them by using your general organic Chemistry knowledge. Draw the structures of reactants and catalysts (if possible, draw structures in such a way that can be visualised in 3D), and for most cases, find out the electrophile or nucleophile and attacking centre, then draw the arrows indicating electron movement. Comparing the stability of products, in many cases, would lead you to your answer.