I use exercise, meditation, mainly, I also use hypnosis audio recordings with binaural beats to relax, knowing what relaxation feels like you can aim to increase the amount of time you want to spend in that state.
At the same time someone mentioned exposure. This works of course with spiders or buttons - expose to the feared object gradually. But for many people the feared thing is anxiety itself. It's just a state. It won't kill you, fighting it will make it worse, wishing it away won't work. I adopted a policy of feel the anxiety and do (whatever the thing is) anyway. Now things that would have me shaking barely register. Also I learned to love that feeling when I reframed it as anticipation. I made friends with my anxiety, welcomed it in as a friend and neighbour, allowed it completely and it seemed to stop knocking on the door so much. I still feel it, but ride it like a wave.
Without anxiety none of us would be here - the chilled out ancestors got eaten by tigers, the anxious ones with their flight/freeze/flight survived to pass on their anxiety. I sometimes see it as a parent, all the anxiety is doing is tryng to keep me safe but I refuse to let it wrap me in cotton wool. Yeah, without any anxiety we'll wander across a road and get hit by a car, too much and we won't leave the house.
Anxiety and excitement are pretty much the same feelings in the body, it's how we frame it that makes it excitement or anxiety. As Hamlet says "there's nothing either good or bad but thinking makes it so". I suppose that's how working with thoughts can work for some people. Personally I find trying to deal with anxiety through thinking like a fly trying to ride an elephant but it works for some!
