How do I get better at writing?
Writing is a skill, but it's often treated as an art. People feel like they should be naturally good at it, and are embarrased if they aren't.
The single best thing you can do to improve your writing is to do it. A lot of it. For many years.
One shortcut is to watch this three hour video The Craft of Writing Effectively by Larry McEnerney. I hate nearly all videos, and always prefer to read information instead. I never recommend videos. This is a great video and you should watch it.
One of the core concepts from the video is that most people were trained to write high school essays, where improving and demonstrating your own knowledge is the only goal. The reader (your teacher) is paid to read your essays, and no one else would ever do it voluntarily. To create valuable writing, you have to think about your reader's goals, which are very different from your high school English teacher's goals.
Ideally, your writing should benefit both you and your reader, but always avoid writing that simply proves your own knowledge without benefit to anyone else.
Once you're done, read On Writing Well: The Classic Guide to Writing Nonfiction by William Zinsser
Writing a lot
The best way to write a lot is by doing it. Try docs.new or other text editor of your choice. Aim for a million words, and then another million.