There are so many ways to reduce test anxiety. It might be different from one person to another. What works best for one might not be the best for others. Knowing our own strengths in overcoming test anxiety is crucial. But most of the time, we want to take short cuts rather than exploring our self.
For me, reading helps to help me regain composure. What kind of things that I read? From holy scripture, Al-Quran (with the translation. So when I read the Arabic verses, I would take a moment to read the translation to understand the verses that I have read) to magazines (and tabloid. I pick up the habit to read The Guardian UK and Dailymail when I was in UK). One of my favorites is Psychology Today (online version). I came across an article about managing test anxiety by Guy Winch. HERE is the article.