Everyone’s heard “fake it til you make it” - people usually say it as a joke. The thing is, it absolutely works. I grew up being bullied in school, so it was not particularly natural to just walk up to people and start talking to them. It can definitely be a bit daunting. The thing is, even if you’re incredibly nervous, all you have to do is act confident. It literally does not matter if you are or not. When someone sees you acting confident, even if you’re not, all they see is the confidence. That’s all they’ll remember. If you do this over and over again enough times, over time, the confidence starts to become less and less of an act. 

Sometimes it can be helpful to identify some role models and people you look up to. See how they talk and act, and try and emulate that as part of your “character”. Over time, what was initially forced will start to become natural.