Why I’m nervous in front of public and how do I overcome it

I admit that I’m very nervous in front of public especially when to present something. I don’t know why I’m too nervous especially in front of my lecturer. Maybe I’m too excited. Sometimes I feel very nervous because I afraid my English language not too good compared to my friend. I also feel so shy when to face with other people because have a certain group of my friend has a good in English language and I think they are like competitors for me. The environment also effect on me because sometimes I feel not comfortable with the environment that's why I can't pay intention on my presentation. But I have my own ways to over come my nervous. Firstly, I will try my best to do what I suppose to do and ignore them, I don’t care what they are saying. Secondly I will control my nervous perfectly, be a confident and only trust myself, so that I can relax my mind and focus it. Thirdly, I will prepare early, so that It's can reduce my nervous and when I want to present something I know what I want to talk to them because I have my own point. thank you