I focus on creating and building a community of people by writing engaging, valuable content.
Working at a startup means that there's a lot of variation in my day-to-day work: some days I'm wearing the "PR hat" and talking to the media, sometimes I'm managing our social media accounts, sometimes I'm helping out writing internal documents, etc. But if I were to zero in on what makes a great day, it's any day that lets me devote most of my hours to writing. I basically get paid to take big complicated ideas and explain them in ways that my audience will understand and enjoy - it's awesome.
Here's the first step for high school students
Find something that you love or that you're interested in, and just start writing! Whether you're passionate about music, or fashion, or whatever, if you start honing your skills and creating interesting content on that subject, there is absolutely a publication out there that will be happy to feature your work. Just make sure that it all stems from a passion, because you're going to be researching and writing about this subject all day, every day.
"You can't major in English. What are you possibly going to do with that degree?"