first of all find out imp. chapters of phy.& chemistry and then start ur preparation ,,,,and learn all the formulae and organic Chen. by heart and for biology take a handbook bcoz it will help you in last minute revision
give ur best
all the best
if you read 1st time then it's difficult for Max score. and if you study before but some time get off then don't worry read again all materials you can get easly Max mark but remember that be frequent for both sub bcoz I am also start before some days.