Every writer has a special, figment-of-your-imagination, someone sitting on their shoulder telling them about all their grammatical mistakes and spelling errors. This special someone's name is Eddy and he's your inner editor.
Or maybe he's a she, and she resembles an evil English teacher on TV. Regardless, they are still an annoyance and hard to control.
In my experience, Eddy has been a part of me for as long as I can remember. Because of that it is incredibly hard to tame him, especially when you're a perfectionist like me. So what do we do then?
One of the better solutions I've found is to set a timer for yourself (or set up a word war with your fellow writers) anywhere from five to fifteen minutes and just write. Write nonstop until you hear that timer go off. Then when time's up, I go back and edit like a grammar fanatic.
How do you deal with Eddy?