If you look at people / startups who have succeed you can always trace it to an unquenchable desire to think/collect/process more information about their problem area. Sometimes this means doing a phd at Stanford on information aggregation (google) and sometimes it means living your startup for a year (airbnb).
A/B Testing, mentors, books, blogs, YC, everything is about taking information out of the ether, processing it so that you can use it for your startup, and making progress.
After all, "An expert is a man who has made all the mistakes which can be made in a very narrow field." ~Niels Bohr
By making the mistakes you collect information for the next time.