Always Get Checked by Someone Else!

You know the drill on proofreading and editing -- check your work, then check it again, then triple-check it. Here's the problem: the more you read your own work, the more your brain begins to memorize it (whether you realize it or not). You'll start skimming over words without realizing it and everything will look correct, even if it's not. How do I know this? I sent an essay describing my desire to continue down a "path discovery," leaving out the "of" even though I read through the piece over and over again. That essay was sent off to one of my potential PhD schools. Humiliating when I discovered the error one week later. Give your work to someone else, or put it away for at least two days and come back to it with "fresh eyes" later.