I Have picked up some of the skills in my first Instructor learning. I did start to build and great reference from messing up with the very first class that I had learners, that try to make the class Like a friendly type of learning.  and fell right into it, it was not the best result. I had to be tough at the End of the course, and my students didn't react to my grading. In my reviews at the end.  So yes, you cannot be their friend, as their teacher or Instructor. I am only there to be Professional… >>>

Being Prepared for a new class is very important.  because they can feel when the instructor is stumbling, or hesitating to find a fact or a piece of relative Information, that will help keep the flow and keep them stimulated.  not letting them dose off from the Learning at weakening pace or miss step. Must Prep at least 2 weeks before and be ready for the questions and answers that the students have. show that you care about them. 

I am so far Learning that Students will Look you in the eyes and Lie Just to say something. The patients you need and the need get their individual personal characteristics. then I can Focus on when they are starting to let my Instruction sink in. I really like when they get the aha moment, of discovery that know get it and retained it. I like now I have other students come to me and ask for an opinion, on the earlier discussions, or for advice.