After years of teaching Std. 9 and 10 students, I have seen that strong performance usually comes from simple habits practiced consistently.
Students should revise daily in short sessions, solve previous papers, ask doubts early, teach a concept to someone else, and sleep properly before exams. These habits are not dramatic, but they work.
The goal is not to study all day. The goal is to study with attention, repeat the right things, and keep fear from becoming bigger than preparation.