According to Sian Beilock, a professor of psychology at the University of Chicago, “when students are anxious about how they’ll do on an exam, their worries use up some of their working memory capacity, leaving less of this cognitive horsepower to apply to the task at hand.”
Based on his research (Ramirez & Beilock, 2011), Beilock suggests this strategy: "For ten minutes, write about your feelings regarding the exam to clear your mind of test-related concerns, freeing working memory that can be applied to the exam" (Murphy Hall, 2012).
Murphy Hall, A. (2012, April 13). How to be a better test-taker. The New York Times. Retrieved from http://nyti.ms/HLxR92
Ramirez, G., & Beilock, S. L. (January 14, 2011). Writing about testing worries boosts exam performance in the classroom. Science, 331, 6014, 211-213. Retrieved from http://goo.gl/e8Wp5