Don't lose your weaker students.

When teaching a new class, it's very important that everybody be on the same level, everybody be on an equal level. They won't really be of course, but you have to make sure that the most important elements and structures that you are going to teach have to be familiar to all of your students.

That means that your first class is going to be boring for some of the students. They will already know some of the things so it will be good to intermix some things that are worthwhile for everybody, some things that will definitely be new for some people in that class.

Alternatively, you may want to release some students who consider themselves to be advanced from the first class. This would eliminate some of the braggarts from trying to show off what they know.

This will have an additional effect also. You will then be able to take these students who had been bragging and it will put them in their place. In the next class, in the following class use some of the new elements that you taught in the previous class and when these students are back in the class and they don't know the stuff, you can say you see you missed some of these things in the class. In every class there are things that you have to learn. And they will then be quiet for a limited time and not try to show off and you will be able to control the showing off to some degree.

And this element of showing off is going to be very important. There is always going to be those who are ahead of their classmates and they want to show off. If you let them show off then they will control the class and not you. You will then again lose some of the students. It is very important that you teach everything your way.

With computer there are also many different way to accomplish the same task. Explain that there are many ways to accomplish the same thing in Word, in Windows, or in the computer. You are going to select one and you are going to use it in class. That doesn't mean that the other methods are not as good but it does mean that a whole lot of the students in the class are going to be on the same or equivalent level. If you do that then everybody is going to follow the same instructions. If everybody shows off that they know a different way of doing the same thing then some students, especially the weaker one, will indeed be confused. They will think that it is important for them to learn all of the different methods of accomplishing the same task which is of course, wrong.

When students try to show other ways of doing things, quiet them. Don't allow it and say this is the way we're doing it in this class, although the other methods are correct. That way you are in control of what is done and how it is done.

There will inevitably be students who are going to present their own way of doing things quietly, whispering, or showing off to other students that there's another way to do things. That cannot be avoided but by saying that this is the way it will be done during the class and in class you are minimizing the problem and you are placing yourself in control of the class.