Make students display their student or state photo IDs. Some students have used "ringers" to take tests for them, but making students present photo IDs will help prevent this.
Before the test, inspect nearby restrooms, and ask a colleague or teaching assistant of the opposite sex to help you. Search for hidden study guides, class notes or books. Be wary of students who frequent the restrooms during exams.
Walk around the classroom at the very beginning of the test and occasionally walk around the classroom during it. Take note of students who make sudden movements in your presence.
Watch for students with roaming eyes. Each person should keep his eyes on his paper and not look around.
Take note of students who rummage through their backpacks and purses. Ask students to gather all their materials before the exam, so they will not have to rummage through their things.
Enlist your students' help. Ask them to notify you of suspicious activity during exams.