Coming from "no"
The difficult task is to turn around a no.
Not, "no, I've thought about it, but I'm not interested," but, "no, I feel like saying 'no', whatever you're offering, the answer is no."
If the fractious child or the skeptical prospect or the frightened boss is coming from a place of no, your proposal just isn't going to work.
Shaking that rattle or waving that spreadsheet isn't going to work, because it's not going to be judged on the merits. The facts are irrelevant... if your partner (and yes, the person you're with right now is your partner, engaged in a dance that will end with yes or no) is in search of a no, nothing is going to go right.
The best path, then, is to first work on the 'no'. Not the pitch or the facts or the urgent thing you need approved right now. First, talk about the dance, and the goals, and how it feels to get to a yes.
Then tell me your story.