What should be my strategy to get above 90% in boards class 12th??

To score over 90%, you should need to have solid timetable and effective time management skills. You should create a daily schedule, covering all subjects, and adhere to it. You should set targets and meet their study/preparation goals for every topic/subject. You should know how to utilize time properly. Do smart work as soon as possible.Try to solve more and more problems itself.

Be careful with your weak points.Practicing from the sample and previous year papers is the best way to get above 90%. Give at least 8hours for your study. Keep focus on English specially cbse students.

Have patience feel cool be happy.

Hope it's work.

Thank you

All the best!