FORTUNE — Lael Brainard may spend most of her time negotiating with foreign countries, but the Under Secretary for International Affairs for the U.S. Department of Treasury offered up some tips on persuasive diplomacy that could just as easily apply to the boardroom. At Fortune’s Most Powerful Women Summit, the U.S.’s top financial diplomat said that she employs these three strategies when she’s cutting deals across the globe–techniques she’s used recently in dealing with the euro zone financial crisis:
1. You have to have a plan. “When we sit down with our European counterparts, we have a clearly defined idea of what’s necessary to navigate this crisis,” she said.
2. It’s important to understand their constraints. Be knowledgeable and attuned to how much they can give.
3. Build trust. “There’s no zero-sum,” she said. “We have to help other countries win.”
Brainard said the rules don’t change when it comes to China. “It is the same basic structure in our engagement,” she said, although she added, “We had to find a path forward with China that was more balanced.” Along with intellectual property rights violations, the U.S. was facing a Chinese currency that for years had been deeply undervalued, which was costing the U.S. But she said, “We want China to be with us at the table making the rules.”