Irony: Pervasive punctuation errors in a blog post saying professional authors — real, serious-about-the-craft writers of any sort — always make sure their writing is free of errors.
Punctuation advice of the day: Do not add a comma after a conjunction at the beginning of a sentence.
Correct: And here we go again.
Incorrect: And, here we go again.
If you want a dramatic pause after the first word, use an ellipsis; that’s one of the things it’s for, after all: And… here we go again. Notice that there’s still no comma in the sentence.