how i hv 2 prepare myself for 12th to score above 90%? i knw i hv 2 do hardwrk nd i wil.

Simply working hard does not give the desired result in any field these days. You need to study judicially and your selection should be done very intelligently. Apply yourself more on the subject topics which come to you easily so that you are 100% sure to score 100% on questions related to those.

start working hard from day one, be thorough with the concepts taught at school upto date. Prepare a study timetable alloting adequate time for all subjects. Work hard with utmost concentration, dedication and determination. Give frequent Revision and Recaptulation to the portions already completed