Cold water is excellent. Controlled, slow breaths, in through your nose & out through your mouth is good too. If you can combine the breathing with mindfulness, even better.

The half-smile thing is recommended too, but I don't have lots of experience with that one.

Cold water works for me, but it can be unpleasent physically.

The controlled breathing is easy to do & it often works, at least for a short time. Adding mindfulness to that is much more difficult for me. My mind tends to wander alot when I am getting anxious & being mindful while that is going on is tough for me.

I am trying to incorporate the half-smile thing, but i don't understand it as well as I should.

Hope some of this helps.

Personally, I plan on hiding out at home for New Year's Eve. Not something I want to celebrate anyway.