Hello Rohit ,

Here are the few short tricks that you can follow to get good marks in 12th board :

• Do revision daily
• Give more time to those topics in which you're a little bit weak
• Give mock tests to enhance your time management skills
• Practice PYQs , it will help to analyze the question pattern.
• Do numerical questions more, it has scoring marks.
• Keep Consistency
• Be confident

Note: make sure that you should clear the basic concepts .Otherwise you may face difficulty in exam while answering some questions.

for your reference , you can go through this article ,

https://school.careers360.com/boards/cbse/cbse-class-12-preparation-tips

Hope this helps !