It depends on their level. I don't know how early students begin studying English in Uzbekistan. If they already know a bit of English, you can mix things up. "Good morning class. My name is (your native name), but you can call me Alex. I'll be your English teacher." More than anything, you want to engage them and show them that English is something that is a useful communication tool. You want to motivate them to be interested for reasons that go beyond passing an exam. I've found that respecting my Chinese students and exposing them to popular music and movies is often a helpful motivator, particularly if you choose things that they can understand. I've found that students are generally curious about their teacher, so I make finding out about me an opportunity to get them to open their mouths and speak. So I often begin with a guessing game. I write several numbers and words like blue, 2, 1978, 191, Journalism, California, and 7 years on the board and ask them to use English to guess what these things tell them about me. First I give them a few minutes to talk to their friends. Then I point to the words, and ask them to guess. I start with easy ones like blue (my favorite color), and 191 (cm, my height), before moving on to more difficult ones like 2 (how many children I have). My goal is always to push the students to talk more than I do during classtime (especially in an oral class). If their English level is very low or they are just starting to study English, keep it as simple as possible during a first lesson. You don't want to overwhelm them too much. Try to speak English as much as possible and don't translate everything for them, except perhaps when there is a misunderstanding or a need to explain new vocabulary.

Congratulations. If you want to appeal to teenagers then just call the whole class 'guys'. That is informal. You can say: "Hi guys, my name is Mr Alex and I will be your English teacher. " Ask the class what do they want to learn and write this up on the board. Then ask them to copy all the information in their books or tablets/laptops. Then ask them what English they know already and write it on the board. Make a clear distinction about formal English and slang which is used in movies and music.

Thank you Jura and Kevin very much. Your advice is very very helpful to me. Kevin, they are beginners and I found it difficult to make a gradual plan of teaching. I mean how I should devide lesson time, how much time to phonetics, how many new words I should teach, should I make them read short simple topics and when and  which tenses I should introduce to them. For example if I teach them present simple how many lessons should we spend on it. And should I teach all tenses of this group first or continue with present continuous....?

 

There is one more confusing point for me. If I show any new object (e.g:pen)and hold it in my hand, which article should I use? It's a pen... or it's the pen?

 

I'm going to motivate them via world map I think it's a good way since we they study geography at school. I will tell them if you want to visit this countries one day, you should learn English well :)