I've been editing my novel, about 20 pages more to go before I send it off for more editing and review by my two secondary school English expert teachers. But as I was editing, I could not help but think 'Oh, if I was to read through it again (I've already edited it two times), I would drive myself insane.' The thing is that you'll always find something wrong with it, want to rephrase a word or a sentence, want to delete some things, add some things, it's just an infinite process. That's when you get others to review it for you; for a writer, your writing will never be 'right,' there will always be something that could be 'tweaked.'
Just a few months ago, someone said something along the lines of, 'I like writing, but I'm not sure how to write good enough to draw a picture in the reader's mind.' I said something along the lines of 'Think of new ways to describe things; use words of impact. Instead of saying that the sky is blue, say that the sky is sapphire.' So, here's a picture I found online that was 'spot-on' with my experience and I hope it helps you too: