What is the best way to keep your students from getting out of control? I am new to teaching. Recently I was given the opportunity to teach at my own university (I am currently doing an MPhil from my university).
If a teacher fails to control his students once, he wouldn't be able to control them until the end of semester.

This is my first time in teaching and I am afraid that my students would get out of my control. They wouldn't listen to me, would misbehave and wouldn't let me give my lecture without interruption. 

Please advise me the best way to keep my cool and prevent my students from getting out of control.

EDIT: I have not started teaching yet. I'll be starting my classes from next week.

EDIT2: The students are Bachelors students. I don't actually want to control them. I just want to maintain discipline in my class. I want to prevent misbehavior in my class. I have seen students not listening to new teachers and just pass the whole lecture passing comments.
First, realize that the main reason they might misbehave is the same as every one else, whether they are 4, 14, 24 or 94 years old: they will be distracted if they are not interested, bored. Conjectural factors surely also play a role (if it's nap time, for example), but if you get them interested you increase dramatically your chances of having a well-behaved audience.

Now, with regards to exercising your authority on a crow, the principles are again pretty much the same for 4 years old and 20 years old:


Immediately assume a position of authority. You have to be convinced that you naturally assume this authority before you go to the class. It derives from two factors:

    a. By naming you a lecturer, your university gave you authority over the lecture room. Be ready, but not overly eager, to exercise it.

    b. This authority also derives from your skills and knowledge: you are an authority on the topic you are lecturing. To maintain this, you have to be prepared to teach your topic.
Be consistent. Lay out a set of rules, explain them, and enforce them. They have to appear justified and reasonable to the students, so that you can enforce them if need be. Always put things back in perspective: why are we here, and how this justifies what I do.

To give an example: I always start by explaining that “I will not shout, because my voice doesn't allow me to go through the whole lecture shouting. Thus, if the noise level meets the point where I would need to shout, I will simply stop lecturing.” Standing there, silent, is a very effective way to lead the group to self-discipline (“hey, guys, shush!”). If necessary, I will remind them that even if I cover less material, the exam still covers the whole planned curriculum…
Be pragmatic. If things are going bad for some external circumstances, be prepared to make a justified exception to the rules, for the benefit of everyone. For example, if it's Friday afternoon and all students are exhausted from a week of exams, giving them 10 minutes off in the middle of a two-hour lecture might lead to overall improved productivity.


But most importantly, realize that while first impression is important, it is not “do or die”. Even as an experienced teacher, sometime you will underperform a given day (because you're tired, because you're not committed enough to this specific topic, because …), but there is nothing you cannot correct later.