How to improve the skill at storytelling and paper writing? I have come to see a comment on twitter: "If you define “good ML paper” as “ML paper accepted at NeurIPS/ICML/etc” then writing a good ML paper is probably much more about how skilled you are at storytelling and paper writing than about ML." This comment is about Machine Learning (ML) and the comment is someone's opinion. My question is more general, how to improve the writing skill for scientific papers? 

It would be great if someone can answer in Machine learning and NeurIPS/ICML perspective.
As with most skills, both physical and intellectual, the key is practice and feedback. To be a better swimmer, swim a lot. To excel at it, get a coach who can give you feedback. 

The same is true of writing and many other things. To be a better writer, simply, write. But the feedback is also important so find a way to get that. You will get it from referees when you submit papers, but you can also get it less formally if you share drafts among colleagues. If you are a student, you probably get feedback from professors, but ask them to comment on your writing specifically, not just your ideas. 

There are, of course, books and such to help you be a better writer. Their advice may be helpful: Keep the reader in mind; Be correct but not pedantic; the opening should entice the reader to continue... 

But the books won't make you a writer (or a swimmer). Just write. 

And get feedback.