I am sorry you are having trouble in making friends. However, the situation is easy to change if you take my advice. Here are some tips to help you:

First, why not find a recent hot topic to start a conversation with the person you want to make friends with? For example, you may talk about the news of Yao Ming's retirement. You may share your ideas with others. If you do this, you may feel much close with your classmates.

Secondly, you should play an active role in class work to show your good points and personality. So your classmates may know you better and like to be with you.

Finally, don't worry about it now. You are only a new senior high student. You and your classmates will know each other better and become friends in school learning and activities. Be confident in yourself. You will have a lot of good friends.