how can l became good at communication skill and debating

Communicate more, talk more to people around you , trying expressing your feelings in terms of words.! It is simple. You can do it! Read aloud! Take a newspaper or a book and read aloud. Try understanding the text and after you are done reading a portion of it, start telling yourself about that portion. Do not read now. say whatever you have understood in your own words. You will gain little confidence speaking once you start speaking to yourself. Speak in front of mirror as much as you can.. You yourself can sense the change in you. One thing Mr. Sandeep Maheshwari (Sir) always says "For the work you think you can't do or you are unable to do, tie yourself up in it in such a way that you can't escape." What you can do is set up debates or conferences where it is mandatory for everyone to speak. Then irrespective of anything you have to speak! So you tend you improve yourself. First time it might not very good but then when you speak next time then you will realise you have improved may be not much but a little. If not then you have gained experience and little confidence when compared to the first time! This is how things work! You can watch videos on YouTube in case you feel you are lacking in grammar.