There are two ways to write an ad, or a manifesto, or even an email.
The first way is as you might expect. It involves order, planning and discipline. In common parlance, it's writing when you have a rough idea of your beginning, middle and end.
The second way is equally important and equally effective.
It comes into play when you're stuck with a problem.
Or your partner and you aren't connecting.
Or he's unavailable.
Or you have an idea you need to work out alone.
This kind of writing is like Jackson Pollack's painting.
Let your words splatter over the page.
Don't start out trying to form something eloquent.
Just start dipping your brush into the paint, your fingers on your keyboard.
See what comes out.
See what's behind the part of your brain that's smart, that seeks order and logic.
Let your words drip.
Give yourself an hour and type. Type about anything. Don't worry if it makes sense or not. See what happens.
Then don't read anything you've written. Instead take a walk around the block. Before you come back to the page, walk away from the page.
When you do come back to what you've written, there's probably something there.
A thread to pull.
A pattern that presents itself.
Find what's good in what you've written.
And start again from there.
Maybe this manner will work for you.
Maybe it won't.
But sometimes it works for me.