While I can see a poorly written piece, it’s much harder for me to distinguish an average writing from a great one even in my native language. Being ESL speaker amplifies this problem for English texts.
So please, share links to the writers who delivered great work for your sites and blogs.
You should try https://app.grammarly.com/ even as an English speaker I use it to proof my writing. It is very good.
Thank you, I’m using it (a free version though, does the paid plan help?). Also I always get proofreads on Fiverr for my big texts.
Here are the traditional intros into writing that I have found recently, I guess many native speakers read it in school:
https://sivers.org/book/OnWritingWell (summary)
https://www.amazon.com/Writing-Well-Classic-Guide-Nonfiction/dp/0060891548
https://www.amazon.com/Elements-Style-William-Strunk-Jr/dp/194564401X
And some newer ones:
Interesting story. There was a fashion in the UK in the 70’s and 80’s NOT to teach grammar in schools. So a lot of people of my generation have terrible grammar.
Its hard to know if Grammarly pro is worth it. I got it when they do their discounts. There are some nice extra features but the free version is probably enough for most people.