Do what you haven't done before, do what you didn't expect doing. In school or work, just be more prepaired for what is to come, so when asked a question or when people speak about a topic, you will be ready to add up to the conversation or give the right answer. Knowing you know something, makes you be able to speak it out knowing people will not say you're wrong. Do a sport, feel stronger, more freedom, or do a sport with a team, bringing confidence and teamwork on you. Accomplish more, the more things you achieve, the better you feel about yourself and the less shy you will be. Move on, ignore what others think, be who you are, and be smart enough to know what you are saying, before saying it at all.