I give them some ideas and techniques of how they might prepare for discussion if they are nervous. I try to address basic feelings and try to make it a safe environment for them to share their views. I find giving context to whatever I'm talking about helps them see why something is important and it allows them to participate more responsibly in their own education and interactions. I feel like teachers sometimes don't share their view of why something is important in the class. Helping students see a teacher's plan and scope and goals for the class, even particular exercises and readings helps I think.
Teaching is a learning process as well.
Being an effective listener as opposed to an active talker is generally more beneficial in the short and long term.