For some, its a natural born talent to be funny. Some people, its the stories about there life and how they swing it that makes them funny, adn finally for the unfortunate few, there is no way they are funny unless they look up jokes online. Just go on stage not trying to be funny, tell the stories in your life that are rare momments. The ones that are either messed up, rare to happen to anyone, or just something that makes fun of yourself. Some stories you will need to "expand on" just to throw the punch line out there. Pratice all the time, and just live, take notes from other comedians, and keep the laughter up.