The way you get better at talking to people is talking to people. At one point in time, I was too afraid to go buy a gallon of milk by my self. I've become one of the most extroverted people I know.

It takes time, but just say, I'm going to go talk to 2 new people today and then go do it. Say, "Hi, How are we doing today?" and then ask them a question about themselves. You'll fail a lot and things won't go as planned, but you'll have a few pleasant surprises too.