You should ensure that you have good knowledge about this exam like exam pattern, syllabus , and important books relating to this exam , and collection of previous question paper.
Stress on important topics-
Physics: Current Electricity, Heat & Thermodynamics, Electrostatics, Wave Motion, Work Energy Power, Simple Harmonic Motion and Magnetic effect of current & Magnetism, Physics of Nucleus.
Chemistry: Chemical Kinetics, Chemical Bonding, s-block elements, p-block elements, Transition elements, Redox Reactions, Coordination Compounds and Chemical Equilibrium.
Mathematics: Vectors, Probability, Matrices & Determinants, Limits, Indefinite Integration, Theory of Equations, Definite integration and Permutations & Combinations.
Practice as much as you can. SRMJEEE tests your numerical solving ability and this can only improve with practice. Attempt a wide variety of questions and use various tips and tricks to save time. Revise again and again. Practice as much as you can. Give regular mock test for better preparation.