Some students have difficulty stopping their negative self-talk. These students cannot just tell
themselves to eliminate those thoughts. These students need to use a thought-stopping technique to overcome their worry and become relaxed.
To stop your thoughts in the classroom or during a test, silently shout to yourself "Stop" or "Stop thinking about that." After your silent shout, either relax yourself or repeat one of your positive self-talk statements. You
may have to shout to yourself several times during a test or while doing homework to control negative self-talk. After every shout, use a different relaxation technique/scene or positive self-talk statement.
Thought stopping works because it interrupts the worry response before it can cause high anxiety or negative emotions. During the interruption, you can replace negative self-talk with positive self-talk statements or relaxation. Students with high worry anxiety should practice this technique three days to one week before taking a test. (taken from: wuvp.edu)