We all make mistakes, and some of us make the same mistakes over and over. Mostly I'm referring to spelling and grammatical errors, even errors that don't seem like errors, but really are. Sometimes you catch them; sometimes you don't. It's when you don't that it's a problem. See, sometimes you write a word and it's actually correct...according to the dictionary. But that word isn't really correct, because the context is wrong. Take for instance the word "breathe". Sometimes I screw up and use "breath" instead. You can't take a breathe. You take a breath. It's one of those strange British things that never went away, and while it might be silly, that's just the way it is and you have to deal with it. I imagine a lot of people don't even realize it's a mistake too (I didn't for a while, and that's because I'm sometimes an idiot about such things).
So, here's a good idea to solve this problem. If you start noticing you make a mistake, and you make it repeatedly (even just two or three times every other story or something), write it down and take note. Put it in a word document or something and then the next time you go to edit you can start doing search and kill procedures to find all the little mistakes. In fact, that breath/breathe thing should be a standard, because many of you may make that mistake and not even realize it's a mistake.
I'm doing this now. I've started putting a list together of things I can search when I edit in hopes that I can catch more of these mistakes and kill them before they end up going to a crit buddy or to a publisher (I made a mistake with one of my last submissions and left some errors in there, and I'm a bit miffed, because I didn't see it for some reason).
So that's my recommendation for solving this issue.