"Say yo instead of hello."
In fact, if you already say "yo" or if you don't say "hello", or if, like me, you work in an environment which frowns upon the urban uniqueness of a hardy "yo!" then you should just try mixing up your usual greeting whatever it is.
As for myself, I am going to revert back to my days as a freshman at Texas A&M University. During 'Howdy Week' we greeted everyone with a cheerful Howdy! in place of the usual salutations. I always love how people up here react to a "Howdy" like friendship and kindness are alien to them; it's adorable.