IMO, it's not writing that you're necessarily struggling with, but editing afterwards. Good writing is a process that includes time to think about that writing. The answer is to write a lot. After you go through a certain volume of text, you get a better feel for it. Andy Weir wrote "the Martian" and he was an amateur; he set daily writing goals (word counts) and stuck to them.
Reducing amount of written text is not something reporters/writers do easily, because to them every word is sacred, because they wrote it and removing words would always amount to loss of detail. Good editors manage to reduce that text and still sharpen the message. Thus, being your own editor can be tough.
In the news world, writing is done lightning fast by reporters who are good at hunting information down but not assembling it into a narrative. The process therefore includes a layer of editing done by someone else who can focus on it. This is why journalism has a bad name with viral articles written by general assignment reporters who have no expertise in the field (an emerging PR, for example) that they're writing about. They're expending minimum effort for the greatest return, and that's their job. Compare those to print articles that have had attention, and you'll see stark differences.
My advice is: I suggest you follow copy-editors to see how they do things; many of them have blogs, some offer courses, but more than anything they give you impression that language changes and you shouldn't be frozen when writing. In fact, what they believe in is that grammar is a living, changing thing. When you see how copy editors transform text, it becomes eye opening.
John McIntyre writes a blog titled "You don't Say" about copy editing for the Baltimore Sun (which he's done for 29 years now). Most of his evening shifts start with him grumbling about snipping text (ex: from 28 column inches to 20), which means he has to reduce some articles by 30%. His reductions are somehow always gains to the reader, but he sure can reduce a reporter to tears.
Some simple examples of his editing: "In a prone position" changed to "prone". Or, "... to anticipate the problem in advance" replaced with "anticipated." ; "End result" replaced with "result." ; "Added bonus" changed to "bonus". "New initiative" reduced to "initiative". And these are just small snippets having to do with filler - larger fact-checking and narrative edits are a much longer story.