Hii Tharun!
Usually class 11th final exam is not considered as a board exam. Class 12th is given more preferences. Still, in order to score well in physics, which is a very good decision, you must focus completely on the NCERT textbooks. Follow NCERT and the concepts given in it. You should know the syllabus well and prepare accordingly. Revise what is taught in class daily. Even read the portion to be taught next, so that you have an idea of the concept and eventually grasp more in the class and clear your doubts as well. Practice problems related to the concept and solve previous year question papers. Make small notes and revise daily. Clear doubts regularly with the help of your teacher. If you follow these steps....you will definitely score well.
Hope this helps.
Good luck!