Anyone who's ever had the desire to strike out and write something has probably spent more than a few hours looking for advice. Maybe it's about how to start a book, maybe it's about how to write said book in thirty days or less. Whatever the advice, some of it really sticks and some of it doesn't. The advice I hear most often (by authors and no nothings alike) is "Write what you know".
I'm here to tell you that advice is...meh. Sure it will help your writing if you have some personal experience with the given subject but...meh. I prefer to write what I want to know. For example:
I know diddly nothing about STEM but the main character in my latest novel is a graduate-level biologist. Not only that but I have two supporting characters that are a computer hacker and a mechanical engineer.
I cannot emphasize how little diddly I remembered about high school biology and Lord knows I couldn't hack my way out of a paper bag but dammit if I didn't learn to truck ton for this book. Most of it I will never write in my novel but I learned enough to give me some confidence when it comes up in a scene.
So...yeah. Expand those horizons and write about something you find interesting but you might not know a lot about now. You'll never regret learning something new.
Happy Writing!