If there's one formula to create a cartoon, then we would have ended up seeing similar cartoons from all the cartoonists. Luckily each cartoonist has an individual process to come up with ideas/cartoons. Some get ideas in solitude, some other cartoonists can think only in a chaos.
I'm sharing here a cartoon which was created from nowhere. I began with doing a lazy doodle, but a series of thoughts took me to a cartoon idea. Hope you'll enjoy this process and hopefully it will help some beginners.