Have a smile in your voice. People want to be entertained. And if it sounds as though you're having fun, and you've got a smile in your voice, then the listeners will warm to you. And that can only be good. Now, obviously, don't speak with a smile in your voice. If you're discussing something morbid or sad, that's obvious.

People generally love to laugh as well. So a couple of jokes or one liners never go astray.