I write and produce songs.
In the morning, I like to spend some time on the piano just messing around, not necessarily with anything in mind, but sometimes these are the times when you make your best discoveries. Then inevitably, I get to the computer. I usually work on a mix about 2-3 hours at a time. And later in the day I like to record for a new track, either a piano part, vocals, guitars, or a drum beat. Then late at night I will probably return to a mix or something I recorded earlier.
Here's the first step for high school students
Practice, play, experiment. When I was younger, I wanted to be a novelist, and I asked a full time novelist if they thought I had what it takes. They told me, "Novelists write novels, it's not a choice, it's just what they do." It was then that I realized I was actually a musician, because in all of my free time, I was usually playing the piano. Experimenting is key to discovery as well, never be afraid to do something different, all my best songs have come from doing that.
"Who are you kidding? You can't be as good as the other musicians putting out music, what do you have to offer?"