The sequence, for a team doing it themselves.
Talk to your buyers. Recent wins, recent losses, and somebody who left. Ask what they were trying to fix, what they compared you against and what nearly stopped them buying. Write down what they said rather than what you concluded from it.
Get the right people booked. Whoever can approve the answer has to be present for the whole day, not for the summary at the end.
Start with the buyer evidence and let it sit before anyone responds to it.
Move to the choice the buyer is making, including the choice to do nothing, and get the group to argue about it properly rather than politely.
Write together in the afternoon. One person at a keyboard on a screen everyone can see works better than breakout groups, because the disagreements stay visible.
Test every line against a sceptical buyer. Send back anything that relies on an adjective.
Finish with each person saying the proposition without reading it.
Write it up within forty eight hours while the argument is fresh, and circulate the buyer evidence alongside it. Somebody will want to reopen the decision in six months, and the evidence is what settles that.
Then change the things that are downstream of it: the website, the deck, the sales call opening, the way people introduce the company at events.
Running it without customer input. Delegating the writing to whoever writes best. Ending the day with a shortlist rather than a decision. Letting a group settle on something general because it was easier to agree on.
Yes, if somebody in the group is willing to be unpopular for a day.
A day for the session. The interviews beforehand take longer than people expect.