For me, what helped was doing a Master's Degree. And I'm sure a PhD would have continued to help. My advisors bikeshedded the hell out of every line I wrote in

For me, what helped was doing a Master's Degree. And I'm sure a PhD would have continued to help. My advisors bikeshedded the hell out of every line I wrote in papers that had their names :). They also made me read specific material they had on how to write. But reading all those papers got me used to the model. That said, it may not be the most effective method if all you want is the writing skill.