This is gonna sound like a crock of shit but play Pen and Paper roleplaying games.
No, I'm serious. Writing is a skill that is honed like any other skill that exists: practice.
Practice is fucking mind-numbingly boring when writing because you don't progress anywhere tangible. Everything you make seems trivial, pointless and trite. It's objectively bad at the beginning, and you can see it, but unlike a physical skill you don't have the sense that you're pushing yourself, that you're progressing gradually, because writing as a skill is far more abstract.
Solidify your writing into something that requires writing to progress, some sort of sequence of events where you don't spend an entire year before you've got a result that you can evaluate, like a novel would require.
Text-based pen and paper roleplaying games will constantly use your ability to write, and you will get constant feedback from several other people. Not only does this give you an immediate result from your practice, but it also easily allows you to get critique of your writing style because you by the nature of the game have several people who read all of it.
More than that, it's a hobby instead of a mental exercise, and is enjoyable entertainment instead of a necessity.
I know this is a three month old thread but the board seems dead anyway so who gives a hoot