If you find yourself stuck by either tone or writer’s block, try drafting the book in your email client. Put one section’s title in the subject line of a fresh email and address it to a friend who knows what’s going on. And then, in the body, simply type out the shortest possible explanation or justification of the subject line — that’s your first draft of that section. This can help escape the mental baggage of “writing a book” and get you refocused on the bit that matters: delivering useful knowledge.