In the last few days of your preparation for IIT-JEE, you will be touching on last minute topics. But, that should not lead you to ignore the basics, and neither should you skip revising. Here is a brief look at subject wise prepartion.
Chemistry: Most students who do well in IIT-JEE insist that there needs to be consistent focus on Chemistry, because it is quite different in nature from conceptual Physics or Mathematics. Experts suggest keeping focus on both Organic and inorganic chemistry. Focus areas in physical chemistry are electro-chemistry, thermodynamics and chemical equilibrium. In inorganic chemistry, focus on qualitative analysis, co-ordination chemistry and chemical bonding. While you work with numbericals, watch out for carelessness which might lead to calculation errors.
You should keep in might the reaction groups, species/ functional groups that occur as reactants and those that occur as resulting compounds, catalysts and reaction conditions. Understand the arrow mechanisms.
Mathematics: Be careful about co-ordinate geometry(circle, and other open curves) and calculus related questions. For integration (in calculus), try to work out as much mentally without help of references as possibel. Similarly some focus is required on quadratics equations, complex numbers, and probability. In algebra, some stress on vectors and matrices is quired, and similarly conic sections in trigonometry.
Physics: This subect is more conceptual and intuitive, and ideally you should find it hard to forget. Be perseverant and follow through till the end. Mechanics, Thermodynamics, Fuilds, Heat, Sound are important. And similarly electronics and basic magnetics, electro magnetic induction are important in Electric. Be very clear about Optics concepts.