Writing things down is an easy way to get better.
Writing clarifies your arguments. If you have a point of view about something and it feels muddy, write it down. You’ll see the flaws and strengths in your ideas easily. You can move things around and test things out.
That’s what many people use journals for. Even Marcus Aurelius did, and his private notes became public after he died.
Writing clarifies your communication. You probably write a lot of emails every day so it’s important you’re clear and straightforward in your communication. Using as few words as possible to say something is a skill you only learn from practice.
And finally, writing clarifies your thinking. A side-effect of getting better at clarifying your arguments and your communication means you’re getting better at thinking.