What I find works for me (hi wandering in through Network), is looking at the story in a different format -- even just a different font or opening it in a different program to change how the words are spread out on the screen. If you can print it out, that's also good -- forcing your brain to interact with it as if it weren't the same thing you've been staring at while writing is the key. Some people like to read a story out loud (but for me I tune out and don't really listen to myself sating words, but it can be a good way to notice if you left something important out or got redundant or something.)

I had the fortune to work with very good editors back in the 90s, and their little red marks taught me how to self-edit. You might take a look at some of the previous fannish auctions and see who offered up editing services -- maybe you can negotiate getting a short, older work done so you can see what sort of things they'd suggest changing.