In some cases, the students are coming in with some background in the subject. How do you deal with these students? How can you engage them, get them to learn what they think they already know, and to do this without turning them off or ruining the class for the other students? Part of the puzzle is your own interest and passion for the topic. You need to be able to voice it and express it in speech and action in the class room. If you do not, figure out how to fake it convincingly. Another part is your own expertise and knowledge in the topic. Hopefully, you have had more than a single undergraduate course in the subject and are somewhat of an expert in the topic. Your knowledge and skill must also come across, not as an ego thing, but as someone with depth and breadth that can answer questions, interpret the class text, provide insights beyond the text.
It is important to remember who you are teaching; that is, everyone in your course and not just the top few. You should be careful about picking specific sections of the class to teach to; not just those struggling, not just those with natural skill and ability.
You need to understand the students' perception of success, their objectives, and drivers. You might not agree or teach to these expectations (they might not be well founded), but you still need to understand them and work with them.