Hey - this is easy.
Per the previous post, address somebody as they are introduced to you or how they introduce themselves,using whatever title or honorific you first hear. They will give you info on how to change the way you address them as soon as they are comfortable with you, usually right away. In the case of a male addressing a woman, always default to Ms unless you are requested to do differently.
Most times you will be asked to be more informal quite quickly, and if not, no harm done. You show politeness, and no offense is given.
Mark