Sometimes trial and error. Maybe I think I want or need something so I start and try it but that doesn’t work so I switch to something else. Sometimes my brain has an itch but so does my body. Walking and thinking can be good, so can walking and watching Youtube or Netflix. Sometimes being physically engaged helps me with the itch. Sometimes it also helps to be social. Having stimulation from others can help scratch the itch.
Mostly I’d say try doing something / anything. Sitting with the itch can be maddening. Whether it’s listening to music, video games, Netflix, walking, playing with pets, watching a movie, calling a family member, texting a friend, playing on the phone, seeing a significant other, going to the store, cleaning, or whatever else, I usually try something and then move on if it doesn’t meet that immediate need. It works well for me because, like you said, it changes all the time. Maybe today listening to a certain artist really helped but tomorrow it won’t. Maybe I have the patience for a podcast or a Netflix show right now, but maybe I don’t. Whatever you try or find, good luck!