Good question. I have taught stress and vitality courses in corporate America so first breath meditations.  Every emotion has its own breath pattern so there are three or four that start to bring more oxygen to the brain and calm the nervous system down. Second is drinking Kangen water or electrolyzed reduced water in scientific terms. If the brain is upset it is acidic, our brains are actually suppose to be slightly alkaline.the brain is roughly 80 percent water depending on your aging process.  So drinking a medical grade water  is a game changer.   Third, step away from the stressful person or environment for a moment and doing some basic exercises to change the signals can get a person grounded again. Last, write down the stress or problem to help separate from it. These are what I have found helps people with anxiety.