To become a better writer, reading is key. To be a good UX writer, reading, being incredibly observant and understanding users is the winning combination. A few years ago the job title UX writer wasn't really a thing. UX professionals were simply expected to be able to provide the right words to give users clear paths for success within any application. The ability to bridge the gap between visual design and navigation is where the right words come into play.
The term microcopy arose to better describe what exactly we were supposed to write - a few words (or less) for the right button or link - then up popped another title and voila, we have UX writers.
I am a UX Writer
A long time ago I wrote an article called Writing For The Web. Then I adapted it and called it Writing For The Screen. I wrote what everyone focused on usability already knew; users didn't read screen and we needed to be incredibly careful to create content in digestible chunks since they were scanning. I reiterated what Jakob Nielsen said and told people to edit, remove useless words.
I offended academics by telling them to stop using multisyllabic words, to write for an 8th grade reading level, use the plainest language possible and cut half the words from their pages. I bothered developers who let error messages confuse the hell out of people. I pissed off product managers who didn't want to focus on revising the words on screen after screen within complex enterprise platforms. I crushed marketing people who wrote clever tag lines and flowery copy that cluttered screens.
I keep doing all that because I am a UX professional.
UX writers are the UX professionals who should know each of these concepts and apply them carefully. To be a good UX writer, pay close attention to usability fundamentals while keeping a close eye on how people use apps, always look for places where the words can be improved and never, ever write click here.