Hi Sushmita! Now that there are around 20 days left for the test, I believe you have completed your preparation and taking mock tests and analysing them. As far as time management is concerned, you should now focus on the time management strategy for the exam. As far as preparation is concerned, at this last stage, spend maximum time brushing up your strength areas and don't focus much on your weak areas as there is hardly much time left to improve. Moreover, don't start any new topic now.
Take full length mock tests everyday at the time of your test (forenoon or afternoon session) so that your mind and body gets adjusted accordingly. Now for the exam day, the order of sections is already decided and you get one hour to answer each section. The trick is to go through all the questions in a section for the first couple of minutes and mark the questions which you feel you are comfortable in. For the Quantitative Ability and Data Interpretation & Logical Reasoning sections, do not spend more than two minutes for one question. For sitter type questions, which would take more time than you had expected, skip those and move ahead. For Verbal Ability and Reading Comprehension, make sure you read the passages carefully. You need not attempt all RC passages, but don't leave out the Non-MCQs as negative marking scheme is not involved in such questions.
Always keep at least 5 minutes buffer time for each section and Review the questions you skipped so that you can go back to them and answer if possible. Also, revise the answered questions to rule out chances of mistakes. Wish you all the best!