Spend time on this subject. Physics may have some concepts which are difficult for students to understand in some cases. A key example is electricity and magnetism. Spend extra time on topics you find difficult and most of all, remember to do PAST PAPERS. These will be your light in the dark, your teachers, your friends. Continue to do them, and remember to leave one unsolved before your examinations. This will orient your mind for the examination and let you achieve the maximum marks possible.