During the worst of my anxiety, my T taught me to make sure I wouldn't be interrupted by anyone or anything. Better achieved when I was alone. Then she taught me imagry. I've already got a vivid imagination so it wasn't hard to do. You can play ocean music if you prefer the ocean or forest music, if that's your preference. I play it really low so that it will not interfere but boost my imagination. To relax your muscles, take a few very slow breaths while squeezing all of your muscles at the same time, or first your legs, then your abdomen, your chest, your back and arms and finally your head. If you can, see all the anxiety going out of your body when you exhale.
I go either to a "safe room" that I constructed when in therapy but it's mostly for the child in me. Or I can go to the mountains with all the sounds, smells and sights, or to a praire with everything that entails. Sometimes I can even conjure up a little friendly animal. This place HAS to be safe! Nothing can intrude without your specific permission. Then I just allow myself to "be." There's nothing to do or not do, no worries, nothing that you don't want.
You can either set a timer or just bring yourself back to where you are slowly. Your mind accepts what you imagined as if you were really there. Your "batteries get charged." I still use this imagery when I just can't cope anymore with all the stressed of life. I recommend it highly!!
BTW, if you don't have an active imagination, it will take practice, but it sure is well worth the effort when you finally get it.