Establishing authority in the classroom What is the best way to establish your authority as the instructor in a classroom?

I am asking from the perspective of a graduate student who will be TA-ing a large class for the first time. But I think similar advice could be said for new assistant professors who still look like students.
The position of TA automatically comes with a certain amount of authority, which is referred to as legitimate power. Having said that, you can increase your perceived amount of authority by demonstrating expertise in the subject area (expert power). Expertise needs to be combined with the ability to actually communicate the complex material as well. It is much harder to communicate complex information than it is to be an expert in complex information.

In addition to these skills, authority can be further enhanced through softer skills such as demonstrating care for the students and providing additional support when necessary (referent power).