Let me share a little piece of advice I got from Karl Schroeder comments while he was Writer in Residence for the Merrill collection and was kind enough to look at a story of mine.
Always make a final revision of your writing from hard copy, as in, print the dang thing out, read it over, and mark it up with a pen.
I just finished revising a short story previously called "Sacrifice" and now named "Into Each Life, A Little Rain Must Fall". I printed it out and went over it with a fine tooth comb, and discovered so many things the needed alteration and fixing it's not funny. And this is a story I'd gone over a few times while it was on screen!
Aside from catching more things, editing from hard copy lets you see how the story is going to appear on the written page much clearer than reading it on a screen. And, I find for me it's a little bit easier on the eyes.
So, from now on the final edit on anything before I send it off will be done on paper. I owe it to myself and anyone who ends up reading my stuff to produce the very best I can. And to keep working at getting better.