So let me explain some things to you.

1. Certainly there are writers who get 500 followers in a month. There are several reasons for this. They had a large number of followers on other platforms, and those followers followed them to Medium. Another reason would be they write articles about how to write or how to earn money. Some people also lie about the kind of money they have made.

2. Follow for follow does not work. A follower is not a reader. To gain a reader, there is only one way - write extremely well about topics that people want to read. Provide the kind of insights that are unique and not a copy of what other people are writing about. I'm sure you've read my 'about' section. I have more comments like that than I could possibly keep - I was first published in 1961/2 at 10 or 11 years old. The tears sheets are in my portfolio if you want to google that.

3. Pure luck. If you join a site early, it's easier to gain followers. If you make friends with someone on the staff, or someone on the staff likes you, you are more likely to gain traction. If you write the right article at the right time, it will push you into the limelight. All luck. Very few people tell you that luck has a great deal to do with it.

This article might also help you in your writing.

https://medium.com/born-to-write/stop-blogging-start-writing-c1a529772553