SEO Experts on Medium: What's your advice for a writer picking up SEO as of today?

I'm not new to writing or freelancing but I'm trying to figure out this whole SEO thing (how I can do it in-house). I decided to pull the trigger on this as my new years resolution. I wrote a few articles on medium before, but I hadn't been thinking of it from the SEO perspective. What should I be thinking about to really punch above my weight on Medium specifically (or similar sites)? Should I kick off my own [wordpress.com](http://wordpress.com) site too?