The best thing a person can do to improve their own writing is to edit others. Editing forces you to turn a critical eye to the structure and flow of a piece of writing, rather than merely treating it as information. Over time, it organically teaches you how to optimize the text. 

I like to think of writing as akin to sculpting. The first step is to drop the required amount of material in place and impose a general sense of order over it. But then you must begin the harder part of chiseling the intricate, beautifying details that turn it into a finished product.

Not until I began to write professionally did I realize the importance of editors. I have never met a writer who did not need an editor, or did not benefit from their relationship with one. Today I also work as an editor for others and find it a rewarding experience. Not only has it made my writing better, but you really never forget a piece of text that you edit. I can still recall in detail all the articles of others that I've worked on.

Writer, podcaster, and commentator on foreign affairs and politics. Runs /dropglobalnews

Clanker Broadcasting Service /cbs

I have never worked with an editor and I do creative writing, but I find there are two lesser alternatives to a (good) editor: 1) Beta readers. 2) You yourself a month or two removed from your own manuscript. You can very easily pick up on silly weird mistakes given enough distance from your work.