I think there are two important elements to the 20-Mile March:
Figuring out the fundamentals of your business, and
Sticking with them and making steady, consistent progress.
Most startups are still figuring out the first part, which is why I focused on the empirical creativity section first. You’ve got to figure out a winning formula, but once you do, drive at it hard and consistently. Avoid the over-reach, but also do everything in your power to keep forward momentum constant.