To increase your chances of admission into NMIMS Mumbai, it is recommended that you aim for a score of 209-210 in the NMAT exam. It is also important to clear the sectional cut-offs. However, it is essential to note that a higher score does not guarantee admission while a lower score does not necessarily reduce your chances of conversion. 

Your performance in the GD and PI rounds is also crucial for the final shortlist. Therefore, it is important to perform your best at every stage of the process. The final shortlist is based on the cumulative scores of the NMAT exam, GD, and PI. It is also advisable to talk to the faculty and alumni to get a better understanding of the admission process and make an informed decision.