Careful consideration is needed. Word selection, grammar, all while keeping the reader in mind. You're sending a message, afterall, so the message should be readable.

And then if you want to tell a message with a different tone, again, you must consider differently.

The considering can be strengthened with exercise.

I can't imagine worrying about signaling as I write: what a huge distraction.

The problem is: this type of thinking and writing takes a lot more time and attention.

How much consideration should you put into a message? It's a personal answer, but also one that can be constrained by time.