No, it’s not the Nike slogan (or whatever shoe that was), but it IS an answer to what so many keep asking:
How do I start writing?
I always answers with “just do it”. I know that’s been used over and over again, but honestly that is what works best for me and many others.
Sit down and just start writing whatever. It doesn’t have to be good. There’s this tendency to think that we have to write everything perfect the first time. Not at all. That’s what editing is for!
Write. Even if it’s just a description of the scene you want to flesh out later, write that down and come back to it later.
You’ll find so much more freedom and energy when you just put pen to paper or fingers to keys.