I used to start in MuseScore but I eventually found that a little too limiting so now I tend to open up a DAW directly. However I also find that sometimes it's easiest to get started sketching ideas with actual physical manuscript paper and singing ideas to myself
For art I basically always start with pencil on paper even if the piece ends up digital. Way easier for me for some reason.
For art, I sit down with a physical sketchbook and pencils.
For writing, I use OpenOffice Writer. I can't physically write down stuff like this.
I start almost everything with my guitar
or a piano
something comes to me and maybe half the time I throw it in fruity loops and try to work out the rest of it (though I used to use forte or some other scoresheet thing), and half the time I write the rest on my guitar
probably have written 10 total songs directly in a digital format
i open famitracker and slap the keyboard until something happens
depends on how I'm feeling at the moment for the most part! Sometimes with art I'll sketch on paper and then go digital, but usually I'll do one or the other. For bigger projects, like coming up with dnd ideas or any kind of well thought out thing I usually start in a physical notebook and just scribble down key ideas/terms
Once I'm hit with something I want to make, I start by thinking about what the best medium would be to make it in. Sometimes it's watercolor, sometimes it's cross stitch, graphite, etc etc
sometimes I go "musical!" and then rerack to what's probably going to end up being colored pencil
But generally when I want to make, rather than going "I want to make" I come into it already with some kind of idea
Usually the "ideas" phase happens when I'm away from the canvas, like when I'm daydreaming at work or whatever. It's usually a pretty vague "I should draw this character doing this" and it becomes more refined once I start to actually draw it
Otherwise my first actual step when I'm in front of my tablet is finding some good reference pics if I don't already have any, whether it's for what the subject itself looks like or for the pose I want them in