The same holds true whether you're attempting to establish initial rapport and trust with someone or building your credibility cache within your organization. You need to be able to communicate your own expectations and negotiate the expectations of others.
The spirit of negotiations lies in the expectations between the parties. You don't need a contract in front of you for others not to expect something from you.
Managing Your Expectations
When you enter into negotiations, do you know what you expect to get out of it? Whether you're in a conference room, walking the halls at work, or discussing project details over the phone you'll want to know what your formal, i.e. tangible needs and your informal, or emotional, needs. Your negotiations plan must capture both aspects; otherwise, you'll miss opportunities that present themselves, as well as risks that lie below the surface.