Write for somebody specific.
It can be useful to consider writing for a specific individual, alive or dead, doesn't matter. Just pick somebody and write to them. Explain your point in a context and tone that they would enjoy.
There are many alternatives, but writing for "everybody" without a clear inteded audience is often too unconstrained.
Constraints can be useful!
I find that this approach works well for articles, emails, and tweets as well.
You don't need your target individual's permission to do this. You don't need to share the resulting work with them either.
It's a personal constraint that can make writing flow a bit easier.