Give them input and they'll know you listen, and that you care. Ask them questions that help them understand you know their concerns. The third global thing you need to do is help your users speak to you. Get them started, get them talking to you. Ask them about their work, their families, their jobs.
People love to talk about themselves.
You can be business-like or informal, whatever fits the person and the occasion. Be cheerful, pleasant, and helpful. Be efficient and courteous . These things are likely to foster trust in users . Ask questions that users can easily answer at first, then, get to the details as the conversation moves on.