To get Boosted, it's not just about writing "really high quality," it's about understanding the kind of quality that curators are looking for when they're assessing stories.
If you really want to get into how to get Boosted, here are some great resources:
Medium's Quality Guidelines, which includes many examples of Boosted stories:
https://help.medium.com/hc/en-us/articles/360006362473
The manual curators are trained with when they're learning how to assess story quality: https://medium-teamspace.notion.site/Medium-Curation-Manual-How-to-Assess-Story-Quality-01277bfcb0d94894b80f4aa1be76ade9
Our head of curation's recent story on the Medium Blog:
https://blog.medium.com/updates-to-our-quality-guidelines-for-sensitive-content-e01ff8f55ad5
The most frequently missing piece I see for writers these days is the personal expertise aspect -- your story needs to convey why the author is uniquely well-suited to writing this story. Generalists don't do very well with our current quality guidelines. When Boosting stories, our curators really need to understand why you, and you alone, are qualified to share the story you're writing. We want real human stories from subject matter experts... not dry Wikipedia excerpts.