As a sequel to the Smartfiber project, a demonstrator was required to be built for a PIC (Photonic Integrated Circuit).
I believe know-how is built on experience, perseverance, and no fear to fail.
From these skills, the most important is to be fearless to fail.
Ideas usually gain trust through simulation and theoretical assumptions. However, the only way to validate an idea is to build and break. Every failure learns you more about the end product than any theory or simulation could. In this context, proper data-management of every build and test is key.