Beverly Hills 90210 Donna Struggles With Her SATs

In the first half of this clip from the original Beverly Hills 90210, Donna gets upset when her friends discuss college, and then has a hard time taking an essay test.

Test anxiety is a mixture of heightened physiological arousal (nervousness, sweating, pounding heart) and excessive worry. What are some good strategies to overcome it? How is test anxiety related to the Yerkes-Dodson law?