We've all got our little words and phrases that crop up in our writing over and over again, those writing weaknesses that we don't notice, but cringe when someone points them out. I found mine. And boy, did I cringe.
My weakness: I blanked. By that, I mean that I overuse the phrasing "I *ed" such as I looked, I walked, I started, I moved, I gathered. My book is in first person, and while there is no way to completely avoid that phrasing, it is not the most effective way to convey the action that is taking place. As was pointed out to me very recently, too much of it leads to a boring step-by-step run down of what's going on.
I am now enternally grateful to Gary Corby, who wrote a life-saving post on Advanced Searching in Microsoft. With the help of his post, I was able to highlight every instance of "I blanked" -- all 745 of them. (Yeah. Major cringing going on here.) I am well on the way to fixing these (only 650 now!) and my writing is much stronger for it.
On a side note, out of 10+ beta readers, not one commented on that. But a publishing professional did, so guess who I'm listening to.