Comic strip writers have to create characters who are easily understood but with enough dimension to sustain hundreds of short storylines. So maybe the rest of us could learn something from one of the best.
I think the best comic strip since "Calvin and Hobbes" is "Cul de Sac." In the video below, the writer and artist Richard Thompson talks about how he created the characters for that strip.
PS: Unfortunately, Thompson has Parkinson's. Recently several of his cartoonist friends took over the strip and gave their interpretation of his characters while he underwent treatment.