Start small. Just start by smiling and saying "Hi." to random people Than start a conversation with people. "How is your day?" If the person in line in front of you is buying something you have been thinking about trying ask them how well it is working for them.
Join clubs and sports. That way you are bound to be going everywhere and talking to more people and such. Also go out with friends more like to movies park beach and such. Look for activites that involve more people even if you dont know them cause like that youll have to get to know them and all