Hi!
Trying to get 90+ may not be easy but it's possible ..
1) constant hard work
2) understanding concepts and trying to frame your own questions and finding a solution
3) solving lots of question papers and checking the solutions for knowing pattern of mark distribution
4) writing each answer step by step and emphasizing good points by underlining key words ( presentation plays a key role )
5) making flowcharts and diagram based learning
6) making short formulas so as to get the answer easily and verification
All the best
Pratiksha (CR@CAREERS360)