Where do ideas come from? From everywhere. From observing what's going on around you, from overheard conversations, from reading current newspapers and magazines, from news radio, from watching TV. I carry a pad of paper and pen with me to jot down ideas. I watch people from benches on the boardwalk. I walk around New York and take in the sights of Times Square, the High Line, tourists gazing up at buildings with their cameras, signs on restaurants and in storefront windows. I also get out to more rural areas and observe what goes on in small towns, in diners, in parks, on long stretches of highway, listening to what the locals say. City vs. country. I've lived in both places. Lots of humor there. Because I often write in the library, I look at books which list cliches, proverbs and catchphrases. After several hours of writing down ideas, I let all this settle for awhile. Maybe later the same day or the next day I'll start writing. Common phrases can be twisted by substituting one or more words, especially at the end, creating a surprise. You can also use the opposite of the phrase. Finally, you can have these phrases spoken by someone in a new, unexpected setting. Again, a surprise.
It's important to get a lot of ideas. More than you'll need. Some will become great cartoons; some will stay, untouched, in the notebook. I can't say how the mind works but having a lot of ideas to work with (I work with words) can lead to great ideas.
I think it's important to follow a regular schedule and not wait for inspiration to strike. I know I'm more productive in the morning. I'm at my desk early and because I write for many cartoonists, I have a regular schedule for who I send ideas to and on which days. I also write to-do lists. (You won't believe how much satisfaction I get when I get to cross off items from my list!) This may not work for everyone but it works for me.
To write humor, I believe you have to have a skewed way of looking at things. This is really important. You have to be critical and you have to be able to see the humor in what's going on around you. And then you have to take the big step of putting your ideas on paper and sending them out. Many won't be used. But when you get a great idea and see it in print, or online, it's fantastic!
Any questions or comments, e-mail me at: firstname.lastname@example.org.