When I like to plan for a campaign or write anything for my games, I like to queue up some music.
Normally I pull up some Apple Music and look under "Focus" and I pull up Trance type music. I've noticed something with a constant beat or rhythm helps me concentrate big time. I am not sure why this works with me so well and with Trance or EDM. I really don't like the music that much at all, but it works for planning games.
Here's my current list
What works for you?