Leverage grows when walking away is genuinely possible.

Leverage is not a matter of tone or technique. It comes from the honest availability of another option, and everyone in the room can sense whether it exists, no matter how it is presented. Someone who can genuinely leave will negotiate differently without trying, and someone who cannot will eventually be found out. The strength has to be real to work.

Rather than practicing how to seem willing to walk, spend the effort building a second option before you need it. Another supplier, another offer, another plan. The preparation is where the position actually gets made.