Work on small extroverted goals, with small goal successes you build confidence. The more confidence the bigger goals you can set for yourself. Take an improv class. They are usually welcoming and it builds confidence in a fun atmosphere. Or sign up for Toastmasters, they are designed to help with public speaking. These things might not make you a natural extrovert but it will take the anxiety out of acting in an extrovert fashion when you need to do so.
Magnussen (not verified)says...
Work on small extroverted goals, with small goal successes you build confidence. The more confidence the bigger goals you can set for yourself. Take an improv class. They are usually welcoming and it builds confidence in a fun atmosphere. Or sign up for Toastmasters, they are designed to help with public speaking. These things might not make you a natural extrovert but it will take the anxiety out of acting in an extrovert fashion when you need to do so.