First of all be aware of the syllabys and exam pattern.You must select the best books to prepare for IIT JAM exam. Make a research for the best books available for IIT JAM chemistry. You can also buy them from Amazon, Flipkart.Test yourselves by solving previous year question paper, solving model test papers which helps you to identify the exam pattern.Start preparing from nowonwards so that you will get enough time to revise.

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