This is what I think newsletters crave to be. [They] should sound as if a clever friend wants to share something with you urgently; punctuation and grammar be damned.
From Robin Rendle’s blog
I’ve come across the line “write as if writing to a friend” dozens of times, but I’ve always struggled with it in practice. I find it hard holding a particular reader in mind, and so drift into pompous monologue.
Something about Rendle’s way of framing it is different. I feel you, the reader, reading this. I respect your time. I care about getting the idea across.