Write the questions which you know first rather then wasting you time rambling in the same question.
Bring enough stationary items .
Check the marks carried by the question and write the answers,so that you wont waste time for questions which carry less marks.
Finish your exam, within 30 to 15 minutes before submission so that you can check for some errors in your answers.
This are the few tips, according to me which will help you to score more marks in exams.!!!