Some tips on writing a humorous narrative is that it must be funny. Not only the joke itself should be funny, but the visuals you show with it. Also, the audience needs to be able to relate. For example, don't make an un kid friendly joke if your audience members are kids in second grade. Another tip would be to make a joke that the person you are telling it to would understand. For example a while ago I was talking in a British accent and someone asked my why. I responded with " Hmmm.. Maybe JARVIS rubbed off on me, good thing Ward didn't though." As I died in laughter the person slowly walked away in fear. (if you dont get the joke it was from agents of SHIELD. Its because JARVIS has a british accent and Ward is HYDRA and HYDRA is a nazi science division in the Captain America comic books and movies.) Some other tip would to not go off topic. Don't be like "Bananas are a good food- Oh the Dallas Cowboys won the football game last night- and apples are good food as well. Some more tips would be to just make the joke plain funny.
My Comedic Monologue is funny because it relates to people on a fandom. I mean we all have to admit that we have found our selves at 3:00 in the morning wondering " what am I doing with my life?". I mean if you haven't you're weird and you should be in the episode of SpongeBob where he says "Hi, I'm normal." I thinks that's why it's funny because even if you aren't in a fandom, you still have shows or books that you stay up late reading/watching.