Fill the canvas.

It's a hack. But it works.

Many artists fill the canvas with paint before they start making the painting. Once the canvas is filled, it's already spoiled. Now, you are just making it better.

Same can be done with a blank page or a blank email. Fill it through with everything that doesn't make any sense, at least not to you, at least not for now.

This might be the hardest step of the creative process. The editing afterwards is easy.