In theory, behavioral approaches, where you train yourself to have a certain calm response to a specific stimulus, is extremely helpful. The problem is that we need to remember to do it. And it needs to be something that can be done with the minimum of props, wherever we are.
So, for minor distress: meditation, mindfulness, CBT and DBT are great. So is, for me, a cup of Tension Tamer or Jasmine tea. I've trained myself to feel calm when drinking or smelling those teas. Lavender oil also works for me. When I remember to use it. As well as certain pieces of music... as long as the distress is minor, otherwise I ruin the music for future use.
I read something last week... on facebook maybe?... about someone who used a clicker to reinforce moments of joy so that when she was not having a good time, she'd click her clicker and remember/experience the feeling of joy.
But if you're in meltdown mode, will you remember your clicker, your tea, your favorite song or pastime? Probably not. Personally, I don't remember to call helpful people at those times, either. Or can't.