The only way is confidence. You need to tell yourself repeatedly, that you can speak fluently. Whenever speaking to someone, maintain eye contact with them. This will help you to concentrate on their eyes and communicate with them rather than dwelling on your speech problems. Another thing, you know, the reality is..people are only thinking about themselves. Nobody really cares man, except for their own selves. While talking to someone focus on how you can make the other person comfortable rather than focusing on your own shortcomings. This will make you confident.