How do you cope with stagefright?

I’ve been wanting to perform for ages, yet haven’t had the chance to until now. I’d be belly dancing probably at a festival or at a dance studio’s open house and am nervous as hell!! I’ve never been comfortable on stage- although I LOVE dancing and I know I’m good at it (I’ve been doing it for 7 years), and I’m looking to change that, or at least come up with a system or method that helps calm me down before getting up to perform in front of a ton of people. Any ideas? How do you cope with performing?