If you want to be funny, you need to convey that something is funny with your face with your voice every part of your body. Very few people can be like Steven Wright, the famous comedian who has the droll monotone one liners for the rest of us. If we want people to know something is funny, we have to convey that with our facial expressions with our tone of voice with an actual laugh. Don't be afraid to laugh if something makes you laugh, too. This will all send signals to the audience that hey, you're having fun. They might as well too.