NLSIU picks the crème-de la crème of the aspiring students and people put in a year or two just to prepare for CLAT to crack the top list. It is not possible for you to prepare just in a month and crack the top 75 in CLAT.
However, if you still do want to try, do the following things and add a little confidence in yourself and you might just win this one:
Work hard and you might just pull it off!