Well cartoons are generally a satire. The image shown are generally in ironic counterpoint to the message in a speech bubble (if any). Like, for one of the practice papers I did, I used symbolism/metaphor of the desk in between the two groups of people as a barrier to belonging. For another cartoon, there's this woman who is 'fatter' than the rest of the skinny girls, and I looked at the facial expressions of the 'group', saying how the similar characterisations of the puffed up lips and the batted eyebrows and pointy nose was a criticism of a society whereby difference leads to alienation, and hence, aims to exclude individuals, rather than include individuals.
I dunno, to me, those techniques seem 'deeper' than the obvious 'colour' 'shading' (unless there's a distinct purpose, and a very good explanation, of course).
