The short answer is: You just start and you don't stop.
Goals are really important too. They help you stay emotionally "sane" during the long-stretches where things don't seem to be "working" or things flat-line.
But, if you stay the course, there is always an audience for good, consistent, thoughtful (curated) content. That's where you can start but don't stop there. Make sure you start building "OG" content too: