1. Repeat your funny book title - JUST THAT!
For instance, while many authors wait to deliver their first point with a three-page pointless epilogue, Jillion Madison, author of Damn you, autocorrect! crafted it differently, and amusingly.
"Damn you, autocorrect!". If you own a smartphone, there's a good chance you've screamed that phrase at least one.
2. DESCRIBE your main idea very specifically. I repeat, describe. Don't just write it.
While academic writing suggests you give a general controlling idea in a paragraph, in humor essays, you do the opposite. Specific description of what you are about to explain fuels humor anticipation of the reader. Check out how The Editorial of Opinion in Nonsense News, for instance, wrote his topic sentence to describe how boring his life working in an office. Hint: Its not just general statement "Working in an office is very boring.".
Last night I had a dream that I came in to work with a fish I just caught and gutted it right there on my desk, then I realized I had fallen asleep watching Office Space. So yeah, what else can I say about how insanely boring my life is without falling asleep at the computer. When I was young, I thought I would have an interesting life. I would be an astronaut, or an artist, or a waiter. Now here I am, twenty-eight years old, wasting what’s left of my youth by writing this article while I am supposed to be inputting last month’s numbers. Even if I had a spouse, or kids, or a hobby – which I don’t – I’d still spend eight hours of every day pretending to be busy so I can eat food and buy drugs. So what good is my life? I guess all I can hope for now is to be a cautionary tale for our impressionable youth.
3. Make a comparison with your idea's opposite
A lil' game of mystery gives a lil' game of surprise. And surprise is what humor is all about. Sally Bjornsen, author of the book The Single Girl's Guide to Marrying a Man, His Kids and His Ex-Wife, does it just right in a paragraph informing how stepmothers are so not celebrated.
"What to expect when you are expecting" is the bible for soon-to-be biological moms (aka bio-moms). Over the years I have purchased at least four copies of this highly acclaimed book of advice for inexperienced friends and relatives who have found themselves in the mothering way. When I gleefully announced that I was in the "stepmothering way," there was no de facto stepmothering guide for me. Instead of a manual of advice on how to raise someone else's children, my friends gave me a bottle of wine and a diary and toasted me with something akin to "Glad it's you and not me".
4. Surprise! - your exaggerated expression can be just the right topic sentence
You have an expression over an idea, whether its an awe or disgust. And Julie Edelman, who wrote The Accidental Housewife, demonstrated how your very verbal expression makes just the right main idea of a paragraph.
It seems like OH-MY-GOD-liness would probably be a more accurate statement. After all, cleaning brings us into a world filled with ungodly and varying amounts of dust, dirt, and doo-doo. Surely not the world we dreamed of when we dreamed of when we imagined life as an adult.
5. Be Sarcastic with the truth
This common 'simple truth' technique in comedy writing is just what you can apply when writing a topic sentence. Again, I quote Julie Edelman.
The other meaning of smart relates to tools that are actually called "smart" or "intelligent". These are robotic helpers that require you to push a button or how to use them. Then you can sit back, watch the tool work for you, or take a snooze.
6. Write it at the end - often
In humor writing, the punchline is delivered last. Crafting a funny paragraph is no different. See this excerpt from Cynthia Copeland's Diaper Diaries.
And, even more important, you may need a reminder that laughter lightens the load. Despite the exhaustion, frustration, and sheer terror that accompany new parenthood, there are funny moments to be cherished and shared. If you can laugh today when your son pees on your just-dry-cleaned suit as you change his diaper, then you will be able to laugh three years from now when the same son pees in his pants during the Little Brick preschool's performance of "The Farmer in the Dell. Humor is habit.
So there we have, the six ways of writing punching topic sentences. Or maybe there are actually seven or eleven ways. You have other ideas?