I edit books, articles, games, blogs, reports, and much more. I also create indexes for books.
I freelance from my home office treadmill desk when I can, walking slowly. The first thing I do is write. I typically have two or three projects going at the same time, so I check my editorial calendar and email. Then I use an indexing program and macros to index books or Microsoft Word and macros to edit books. At my job, I start by checking email, then I might check a game for errors by playing it, or make suggestions on a training module or report. Whatever the office needs!
Here's the first step for high school students
Read The Chicago Manual of Style and the Associated Press Stylebook. If you find yourself getting bored, you probably won't want to get into this line of work. You've just saved yourself a lot of time! But if you find you have a strong preference for style choices in one or the other, you're born to edit. If Chicago is your favorite, lean toward editing books. If you prefer AP, news is your thing.
"If you get an English degree, you'll have to be a teacher."