Generally, I establish the world first before writing the story: establishing rules, constructing lore, designing characters, and building the world. Next, I create a plot line, gather ideas, and I create the first chapter. The plot line gives me a loose guide that provides the story a direction but isn't something concrete I stick to; I let the story develop as I write.
I've created many plot lines for stories that ended completely differently than my original idea. Stories have their own life and you need to give them space to grow.
I tend to multi-task while writing. Most often, I use my desktop with three monitors going at once. Social media on the right monitor, music videos and notes on the left monitor, and the story I'm working on is on the center monitor.
I often write late at night, many times past 2 in morning. I also write randomly throughout the day when I'm not tired or stressing about some sort of scheduled activity.
My mindset varies day by day. Some days, I cannot write if there are any distractions. Other days, I need music or someone to talk to.
When I listen to music, I either have a new song I like playing on repeat or music that fits with the theme of the story; for example, post-apocalyptic guitar music.
My favorite song that I listen to is C418 Sweden.
Man's fear is in the unknown; man's joy is in himself.