Everyone loves a good laugh. Besides, it's relaxing. For April Fools Day, I've "assigned" an exercise for writing a humorous story. Here's some tips on how to keep it light!
1. Keep down the analogies. While they can be funny, if the story is littered with them, they aren't as amusing as Snape in a vulture hat and a gaudy grandma dress.
2. Don't force your words to be funny. Let them flow on their own. Sometimes all it takes is just mentioning something for the reader to be able to picture the scene in their mind. Using funny phrases or analogies are often not necessary, the scene itself is sometimes all that's needed.
3. When reading and writing humor, have a sense of humor. Don't take things personally. Above all, avoid touchy subjects to keep your readers from taking things personal. Despite the inundation of Pollock and blonde jokes out there, a good general rule of thumb is "do unto to others unless they are willing to suffer the same pratfalls."
4. Avoid joking about death. Its never really funny. Neither is rape or other violent acts.
5. Sometimes the best stuff is stuff that's actually happened. Bizarre and twisted seems to be the specialty of life, so take a funny circumstance you've lived through or seen and put your character into something similar. Oftentimes, people find humor in this because they've been there themselves.
6. Fake outs. The reader knows exactly where you're going with this, they almost can't believe it. Then....WHAMMY! It's totally innocent. A turn of phrase, an omission of certain details that the reader's mind automatically fills in turns out to be all wrong. Stories that seem to be taking a sexual turn and it winds up being someone has a cold. Work with the idea, see if you can fake out the audience. If they've fallen for the trick, it's always worth a laugh.
Unless they have no sense of humor!