I think when starting off one of the best things you can do is to start creating an email opt-in page. With this, you are going to start building your email list that gives you direct communication with your audience. This audience is richer than just mere "followers" from Medium etc. I wrote a piece about how you can get people to opt-in that might be a good place to start:
How To Create An Opt-in Off That Actually Gets People To Opt-in
Top persuasion techniques you probably aren't using
You will be able to glean some pointers from there.
It's also important (through the lens of generating an income off your blog/Medium) is to consider your audience and what type of value you want to bring to them. I would assume you are looking to provide value to fellow educators? With that, consider what type of "freebie" you would be able to provide (cheatsheet, free course, guidebook, infographic etc) that can help you get the audience member on your list.
Furthermore, when starting out — I used Mailchimp as my provider. They are free for the first 2000 subscribers so you don't need to invest money upfront when building your list — just time.
That's a decent amount there to chew on.
If you want to go deeper into any of this or anything further, I am MORE THAN HAPPY to open up communication via email — just let me know.
Have a GREAT rest of your weekend.
P.S. On top of everything there (that is pretty technical to say the least) I would keep putting out great content. Content above all will help you succeed in the long-run.