Don't do this. Follow "The Economist Style Guide" instead:
"Clarity of writing usually follows clarity of thought. So think what you want to say, then say it as simply as possible."
"No, wait!" interjects the German lecturer. "I've almost gotten to the verb!"
A recent example for me is Sam Harris' book Waking Up. It feels like somebody could take that book, remove some ornamentation, and state the ideas more plainly. It isn't a difficult text, but I find myself having to reread pages to clear the fog more than I normally do.
Lean prose (Hemingway) is elegant simplicity.
Choppy prose (most amateur writers) is tiring and jarring.
Despite their seemingly shared characteristic of simplicity, it takes a lot of practice to achieve the former.
[1] https://www.helpingwritersbecomeauthors.com/common-writing-m...
I really recommend "The Economist Style Guide". Please read through it, then read again to see how it was applied to itself (!). Then write a short passage, and revise it to adhere to the recommendations -- don't be surprised if this will need several passes though!
You will be surprised how much this can improve your writing, but also structure your own thoughts.
As for picking up idioms, I think it's something that happens gradually as you are exposed to more writing by native speakers.