No matter where you write — on Medium or elsewhere — put the following article on your required reading list. In fact, keep the larger Medium Creators Hub as an open tab you refresh multiple times per day.
It reminds me of a program I conceived and wrote a significant bit of content for when I was full-time at financial media platform, Seeking Alpha. The Seeking Alpha Author Experience. Except the Creators Hub is better.
Sloane Miller and crew crush it with this post on grammar mistakes. Focusing on what seems like minutia to others can help set you apart as a writer. (Feeling the spirit of this article, I double-checked “a part” versus “apart” :-).