You might vary where you sit from time to time. Getting to a section a little early and staying briefly afterwards to talk informally with students and answer questions can also be helpful. When students ask questions, try to help them find the answers for themselves. If arguments develop, try to resolve the disputes by appeal to objective evidence rather than authority of position. If the dispute is over values, have these clarified and respected even if resolution is not possible.
Disputes can often form the basis for library or writing assignments.
In discussion sections it is important to be as relaxed and unself-conscious as possible. Many students enjoy discussion groups when they sense spontaneity and excitement about learning. This does not mean that a discussion section should not be planned or at least thought out in advance. All of these possibilities involve some forethought, but they also leave considerable room for flexibility as the class progresses. If you show respect for students as people in both your demeanor and language and encourage the group to engage in a common learning enterprise, you can make the students in the group feel comfortable and ready to share ideas.