Probably the best method for reducing acute stress and anxiety that I have heard of is eye movement techniques.
ITs commercialized as EMDR (Eye Movement Desensitization and Reprocessing).
A psychologist named Friedberg caught some flack for just putting the technique down in a book in an easy to use manner.
I think he really annoyed the EMDR clinicians that want a 100 dollars an hour to tell you to move your eyes back and forth horizontally . . . or to tap rythmically on opposite sides of your body.
I despise people that complicate simple stuff to make money.
What he writes down is identical to EMDR. Also, eye access techniques are not new, they have been around for along time.
I know several people that use the technique all the time to break negative thought patterns, deal with anxiety, or even simple stress.
Here is a link to the book on Amazon:
Eye movement