I always thought the ‘For Dummies’ and ‘Idiot’s Guide’ books sounded a little mean. Not that I don’t find them just about right for my level.
One way to write humor is to find something a little odd about everyday life and just extend it to some ridiculous degree. That might be my #3 tip on coming up with cartoon ideas, right behind ‘make animals act like people’ and ‘make people act like animals’.
Keep your chin up!