When I started out as a cartoonist I absorbed as much literature about the art of cartooning as I could - I still do. But the most invaluable information I’ve found, to date, is talking to other cartoonists who are working now.
Regarding gag cartoons, some of the most consistently helpful advice many have offered is “let the reader arrive at the punchline/joke themselves”. So, ‘don’t spoon-feed the joke to the reader and condescend.’
If they get it, they get it. If they don’t, they don’t. Sometimes it needs to be re-written or re-drawn, other times it just isn’t their cup of tea, or the reference doesn’t resonate with them, or a thousand other reasons (including “it’s just not that funny”). But never make it too obvious what the joke is right off the bat. Let the reader have to at least figure out what you’re trying to say.
I still work very hard at tryin to make good cartoons that fall in that sweet spot between ‘this is too obscure’ and ‘this is too hand-holdy’. My friend and writing-partner Scott has a term that we use for when everything is literally labelled for the reader, like a giant steamship labelled the ‘S.S. Economy’ heading towards a big iceberg labelled ‘recession‘ or some other similarly obvious metaphor, like a politician holding a briefcase with their name on it. When we get to that point in having to make a joke work, we abandon it saying, “That’s a bit S.S”
If you’re interested in this kind of thing, you can hear more baffling musings like this in our weekly podcast called “Is There Something In This?” wherever you listen to podcasts.
FOOTNOTE: In defence of our dear editorial cartoonists, sometimes it’s essential to have to label things if the cartoons are being widely syndicated and in some cases, translated into different languages and cultures. Sometimes it’s even necessary to have a newspaper blowing in the composition somewhere with a headline relating to the story the cartoon is about, in case the newspaper running the cartoon hasn’t run that particular story… This could be alleviated by newspapers hiring more localised cartoonists to do cartoons about the area the newspaper services, but those days have sadly passed.