how to get more marks during revision

study those topics that have high weightage and easy like in maths ------ conic section..... probability..

chemistry---- chemical bonding, coordination compounds etc...

during revision to get good marks we need to think that before we do it ,that is prepare rough noted for it and keep as a notes for it so it would be easy for us to keep in mind especially chemistry then recollect the idea which we have learn so we could make them so hard in our mind which means thorough. that is the secret mantra behind preparation for "IIT".