For me, the three most important things to consider are:
1. Knowing the subject matter that is within your field of study. For example you may have a degree in criminal justice but lack the skills to teach in the legal courses, or you are an attorney but do not have the applied experience to teach classes on law enforcement, or corrections.
2. Continue to ask questions related to the topic, going beyond the existing parameters of the class discussion to include additional information or issues related to the assigned topic to perpetuate interest in the class discussion throughout the given time period.
3. Keeping then discussion on track, managing the class discussion to ensure an enhanced learning experience.