Humour is the surprise twist that follows the development of a believable story. After you have delivered the surprise twist, stop, smile and wait for the audience to laugh.
The effective use of pause is a desirable technique for any number of speaking situations, but where audience emotion is concerned, it is the essential.
Emotions, including amusement, take time to build up. You have to provide the audience with that time.
Placing the punch at the end of the joke is also important. The last word should be the one that contains the surprise.
