Hi.  To get a rank approximately under 1500, both your JEE Mains score and board percentage must be high. So approximately, around 245–250 marks in mains and around 96–97% should suffice. For instance, a classmate of mine last year scored exceptionally high in mains with a score of 275 and boards percentage of 94.6 and a rank of 850. Hope you make the cut. All the best!