Sir, I m goin 2 give CAT'12. Will strt prprng 4rm dis mnth end solely on self stdy with corspndnce crse. How shud I prepare 2 get atleast 90

Hello Sir, I have completed my B.Tech. this year. I consider myself as an average student. Cant join coaching insti as I live in tier 2 city as a lot of time will be wasted on travelling. I Will be focused only on CAT'12 till the exam. How exactly should I prepare 2 score atleast 90 percentile.