The author from Lamentations of the Flame Princess presents tips for writing adventures, including letting the PCs fail, setting up challenges that are way over the PCs' heads, meaningful not just illusory choices, rewards sufficient to make the players feel it was worthwhile but not so much they won't be hungry for more, let the players set the pacing (if they're bored, it's their job to do something), use many weaker opponents to cause attrition, use random encounters, and make traps special.