I was very fortunate to stumble into my number one career hack earlier on.
My first professional job was as a PHP developer, building content management systems for an agency. I was the only PHP developer at the company, and when I was hired, I barely knew anything about PHP. I had played around with it for my website, which had previously been static HTML (this was in 2003.)
I struggled by myself for about a year. I had a stack of out-of-date books, and I didn't know what I was doing. I looked on Meetup.com for a PHP user group. There had been one, but there hadn't been any meetings for months. At about the same time, I attended a PHP conference in Toronto where I ran into many people from Madison. Everyone asked the same question "Is there a PHP group in Madison?"
When I got back, I started the Madison PHP Meetup group.
For the first six years, I would come up with a talk to present every month. Occasionally, I'd have another member speak, but I probably gave ten presentations a year. The topics were usually pretty basic and about something I needed to learn better.
After running the group for about a year and a half, I was laid off. The company I worked for decided to focus on the networking side of the business and cut custom development.
Two members of my group were owners of another company in town. When they heard I was available, they suggested we go out for lunch. At the end of lunch, they asked, "So, you want to work for us?" This was when I realized that running the group gave me a massively unfair advantage.
Not only is teaching the best way to learn. But running the group was a credibility indicator. The members knew me, and they knew I was competent.
I became Co-founder and CTO of a startup because the founder was seeking a developer by contacting meetup groups. I even got my current job because the senior architect had seen me talk at the PHP conference that spun out of my meetup group.