Establishing authority in the classroom
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).