Ask HN: What tech skill gave you the biggest boost in your career?

Pattern recognition. I don't mean the ability to do regular expressions. I mean the ability to recognize patterns in software development, organizations, and trends in the industry. It helps recognize when you've seen something similar before and know a good approach to dealing with it. This would include design patterns (like Gang of Four), integration patterns, architecture patterns, etc. There are a lot of problems out there that have stable, known solutions to them.

Having worked with many different environments/programming languages/tools

Knowing how to communicate both verbally and written, persuasion, talk to “the business”, navigate corporate politics, building networks internally and externally.

I got tired of being the geek that everyone ignored over a decade ago.

Maybe not a tech skill, but public speaking. I forced myself to give talks at code camps after recognizing it was a glaring weakness of mine. Was hired by Microsoft as a cloud evangelist as a result. There was also a lot of interest from local companies who sponsor those sorts of events.

Git