I’m sorry: I am not a good person to ask this question, since “how did you start writing” for me is “I learned the alphabet and got to work.”
Write every day.
Go grab something like FocusWriter and set the daily goal to 500 words or so, and then grab a random prompt from somewhere like this and just crap out a bunch of garbage. But hit those 500 words. Try to do that for a week.
Then go back and read what you wrote. YES, IT IS HORRIBLE. I hate this step. But it’s critical. Now you’ve got enough space between present-you and past-you that you can concrit yourself. Go back and read what you wrote, out loud if you can, and see what needs fixing.
Then try that for another week. Maybe come up with your own prompts this time, or think of a larger story you’d like to tell. Or maybe not yet, you just started!
The key, though, is to do this consistently. The more you write, the better you get at it, even if you never ever ever show anyone the garbage you wrote in your first week, month, year, decade of doing this.
Aw, now you’ve put a quarter in me.
As far as I am concerned, the only three pieces of truly universal writing advice are “read,” “write,” and “do not argue with reviewers.” (There are people who will tell you that only the first two items on that list really count. Those people are wrong. Unless a reviewer has misgendered you–I once had a reviewer assert that I was clearly a man, based on my failure to write what she considered a satisfying romance–or intentionally insulted you–another reviewer said that it was obvious my obesity had caused my brain to swell, thus resulting in my writing nothing but tripe–do not argue with reviewers. You will waste time and energy and you’ll never win. You’ll just hurt yourself.)
“Read” does not mean “read the classics.” It does not mean “read words of surpassing literature.” It means read. Do I think you should read within the genres where you want to write? Sure. But some people wind up creating genres. Some people read nothing but non-fiction and write the prettiest lies you’ll ever hear. The advice is only universal when you strip it down.
“Write” does not mean “write every day.” I understand where that’s coming from, I really do: I am someone who has always, without fail, written like I was running out of time. Every day, weekends and holidays, unless I’m at Walt Disney World (and sometimes even then). I make myself sick with writing. But that doesn’t make my methodology universal, or healthy.
“Write every day” is one of those phrases that can be unintentionally ableist and classist. It can cause people to say “I know I can’t write every day, so why bother trying?” How many amazing writers do we lose to “write every day”?
Look: you’ll get better faster if you write every day, because practice really does help. But if you can’t do that, because your job exhausts you, because your brain chemistry says nope, whatever, you’re still a writer. As long as you’re trying, as long as you’re forcing words into the world, I don’t care whether it’s 5,000 a day or 5,000 a month or 5,000 a year. Some of my favorite authors only wrote one book, because that was what they could do. They still changed my life, and helped me to become the author I am today.
“Write every day” is not a requirement, I promise.