After reading your letter, here I give you some advices. First and the most important one, you need to build up your confidence. When in or after class, you can try to express yourself to let other people know what a person you are. Second, try to find some interests that you can share with your classmates. When people who have the same interest get together, they can easily become friends. Last, I want to tell you that good friends are made based on mutual understandings, you can't have friends just after one or two chats. So I hope these will be helpful for you.