Working on real world problems without seeking help from Google/StackOverflow, even if it means reinventing the wheel to make it fit for your particular problem

Working on real world problems without seeking help from Google/StackOverflow, even if it means reinventing the wheel to make it fit for your particular problem, or even going through pages of documentation/code to find the purpose of a single function. It may sound like a waste of useful time, but it slowly makes you self-sufficient to deal with any kind of issues later on.