Omit needless words. There's a page in Stephen King's autobiography "On Writing" where he shows an editor's comments on an article he wrote as a teenager. Half of the words are crossed out. Remembering that example improved my writing significantly.
Also, understand that writing is an iterative process. It can take 5-6 passes to craft a good sentence.
My first attempts at writing were monstrosities of flowery descriptions and long-winded dialogues, an awful hybrid prose/poetry. That didn't improve, but I realized the art is getting an interesting message across as simply as possible, not showing off your vocab or pre-empting the reader's imagination.
"The Elements of Style" belongs to that 1% of books that are truly able to change the way you think (and write).
I tried to apply what I learned in "The Element of Styles" and "On Writing Well" to my company blog: https://medium.com/plainflow/how-we-write-at-plainflow-7e994...
E.B. White, the 'editor', was one of the best essayists around, but he didn't particularly obey the rules in his own book.
It does have its critics but I think it's a very useful guide for most writers, and being a small book it is easily referenced and has remained useful to me to this day, much like K&R was when I did "C" programming.
https://www.amazon.com/Style-Lessons-Clarity-Grace-12th/dp/0...