Flavio Copes is a great person to take this advice from. He’s been blogging for “more than 11 years,” more or less consistently. In this post he covers not only what you need to know to be successful, but also what you need to forget.
One of ways I learn best is by doing. I literally decide on a topic I think I know something about, and I drill down in a spiral loop through things I didn’t know, or I didn’t even think about.
They say you never fully understand a topic until you are able to explain it. Blogging is a low barrier to explaining things.